车前的组织培养

报道了车前外植体的愈伤组织诱导及其植株再生的研究结果。单独的外源生长素2，4－D适宜诱导外植体脱分化产生愈伤组织，只有单独添加6－BA时，才适宜再生芽的分化，当NAA与6－BA配合添加培养基中，则有利于再生根的繁茂生长，从而形成完整的再生植株。     

Neuroprotective effects of propofol following global cerebral ischemia in rats

Propofol has cerebral vascular and metabolic effects similar to those of barbiturates, and it is used to maintain neurosurgical anesthesia because it reduces cerebral metabolic rate, cerebral blood flow, and intracranial pressure. Although the use of propofol as a cerebral protectant during certain neurosurgical procedures has been advocated, consensus has not been reached as to a protective effect of propofol on cerebral ischemia. In this study we observed the neuroprotective effects of propofol during global cerebral ischemia-reperfusion injury by the use of four-vessel occlusion method in a rat model. We measured the levels of malondialdehyde as a marker of lipid peroxidation in ischemic tissue, and the results indicate that propofol plays a role in the inhibition of neuronal death induced by brain ischemia. Electronic Publication     

Acute wood or coal exposure with carbon monoxide intoxication induces sister chromatid exchange

OBJECTIVE: The object of this study was to investigate the genotoxic effect of acute overexposure to combustion products originating from coal or wood stoves in patients presenting with acute carbon monoxide intoxication. STUDY DESIGN: In a prospective study, we analyzed the frequency of sister chromatid exchange and the carboxyhemoglobin concentration in 20 consecutive patients without a history of smoking or drug use who had been treated in the Emergency Care Unit of Istanbul Medical Faculty due to acute carbon monoxide intoxication. All of these cases were domestic accidents due to dysfunctioning coal or wood stoves. The results were compared with a control group of 20 nonsmoking, nondrug-using healthy individuals matched for age, sex, and absence of other chemical exposure. RESULTS: The mean sister chromatid exchange frequency per metaphase was significantly higher in the study group compared to the control group: 8.11 +/- 2.39 vs. 6.33 +/- 1.60 (p = 0.008). We found that there was no positive correlation between the blood carboxyhemoglobin concentration and sister chromatid exchange frequency. CONCLUSIONS: These results suggest that acute exposure to combustion products of wood or coal is genotoxic to DNA. Potential causes of genotoxicity include known mutagenic compounds present in coal or wood smoke and ash, oxygen radicals formed during combustion, as well as hypoxic and reperfusion injury mechanisms initiated by carbon monoxide intoxication. Additional studies on separate carbon monoxide exposure from smoke and ash are needed to understand individual genotoxic contributions and mechanisms.     

Phenotypical features of a Moroccan family with autosomal recessive Charcot-Marie-Tooth disease associated with the S194X mutation in the GDAP1 gene

BACKGROUND: The first locus for demyelinating autosomal recessive Charcot-Marie-Tooth (ARCMT) disease was identified in 8q13, where mutations in GDAP1 have been found. Mutations in the same gene have been detected in families with axonal ARCMT disease. OBJECTIVE: To determine the clinical, electrophysiologic, and morphologic characteristics of a consanguineous Moroccan family with ARCMT disease associated with the S194X mutation in the GDAP1 gene. METHODS: Four patients from a consanguineous Moroccan family were examined clinically and electrophysiologically. In one patient, a morphometric and ultrastructural study of a peroneal nerve biopsy sample was performed. Mutation in the coding region of the GDAP1 gene was identified by direct sequencing. RESULTS: Neuropathy was evident early in childhood, walking was delayed in one patient, and onset of symptoms occurred before 18 months in the others. The phenotype was severe: foot deformities and disabilities involving the hands and feet developed toward the end of the first decade, followed by involvement of proximal muscles in the lower limbs, leading to loss of autonomy. Electrophysiologic findings were consistent with an axonal form of CMT disease: motor nerve conduction velocities, recordable in one patient only, were greater than 40 m/sec. Sensory nerve action potentials were either abolished or substantially reduced in amplitude. The morphologic data supported the diagnosis of axonal neuropathy, showing a marked reduction in myelinated fibers and signs of axonal regeneration, including frequent pseudo-onion bulb formations. The 4 patients in this family were homozygous for the S194X mutation in the GDAP1 gene. CONCLUSION: Electrophysiologic and pathological findings support the hypothesis of an axonal disorder in this ARCMT family with the S194X mutation in the GDAP1 gene.     

Improved flow cytometric detection of donor-specific HLA class II antibodies by heat inactivation

Flow cytometry is a powerful technique for T-cell crossmatching but is prone to false-positive reactions with B cells. In this study the flow cytometry crossmatch (FCXM) was performed in 319 cases, using the patient's serum untreated and incubated at 56 degrees C for 30 minutes. Heat treatment inhibited B-cell reactivity in 30 of 39 cases. Flow cytometry testing with latex beads coated with human leukocyte antigen (HLA) class II antigens showed no class II antibodies in sera that were completely inhibited by heat treatment. There was no inhibition of class I antibodies to either T or B cells, or of class II antibodies to B cells. Experiments with aggregated IgG showed that inhibition by heat treatment is likely due to the prevention of complement binding to aggregates or dissociation of aggregates, or both. We conclude that heat inactivation is a simple step that eliminates false-positive reactions in the B-cell flow cytometry crossmatch.     

Comparison of ingestive effects of brewer's yeast,casein, and soy protein on bioavailability of dietary iron

The effects of brewer's yeast, casein, and soy protein intakes on the absorption and retention as well as the incorporation into hemoglobin and systemic iron stores of dietary iron were examined in an animal experiment with growing rats. Relative biological values (RBV) of iron in the rats fed casein (C), soy protein (SP), and yeast (Y) diets were 1.00, 0.31, and 1.77, respectively. The apparent absorption of iron in Y-diet-fed rats was significantly higher than that in C- or SP-diet-fed rats. The hemoglobin regeneration efficiency (HRE) of iron in Y group was significantly higher than those in C and SP groups. As a result of search for iron-absorptive enhancers (IAE) in yeast, RBV and HRE of the yeast-cell-wall-including diet turned out to be significantly higher than those of its lacking diet. These results suggest that IAE occurring in the yeast cell wall may be effective for iron absorption.     

Atopic dermatitis: therapeutic challenge in an infant with dystrophic epidermolysis bullosa

Inherited epidermolysis bullosa (EB) manifests as blisters that usually result from minor trauma. The severity of expression ranges from mild occasional blistering to severe extensive bullae. We report an infant with dystrophic EB worsened by atopic dermatitis (AD). This concomitant skin disease exacerbated EB, because scratching induced bullae and milia. Careful management of AD provided a marked improvement in cutaneous involvement. This report shows that it is important to document and treat inflammatory skin disorders coexisting with EB, because they may influence the overall prognosis of EB.     

Preoperative Hyperoxyradiotherapy of Colorectal Carcinoma

Aim: The article focuses on the radioprotective effect of acute hypoxia on healthy tissues during preoperative accelerated hypoxyradiotherapy of colorectal carcinoma performed as locoregional irradiation including the common iliac lymph nodes. Analysis of early and late side effects and complications.Patients and Methods: In this prospective study, early and late complications were assessed in 50 patients as a function of hypoxyradiotherapeutic dose increase. The preliminary treatment results of this radiotherapeutic modification were evaluated after a median follow-up of 48 months using Kaplan-Meier analysis. Between April 1991 and February 1997, 50 patients (36 men and 14 women) with colorectal carcinoma were treated preoperatively with locoregional accelerated hypofractionated hypoxyradiotherapy. The extent of disease was classified according to Dukes' criteria (A. four patients, B: 28 patients, C: 18 patients). We used a 20-MeV linear accelerator with two parallel opposed fields. Hypoxyradiotherapy was peformed extending from the perineum to the vertebral L4 region. Acute hypoxia was induced during irradiation by ventilation of a hypoxic gas mixture containing 7.8–8.0% oxygen. Total doses of 24 Gy/8 days, 28 Gy/9 days, and 32 Gy/10 days were applied in five, 20, and 25 patients, respectively. Low anterior resection or abdominoperineal amputation of the rectum was performed the day after completion of preoperative hypoxyradiotherapy. The early reactions after irradiation were evaluated according to the Common Toxicity Criteria of the National Cancer Institute (CTC-NCI).Results: Early postirradiation proctitis was documented in three and early radiation-induced cystitis in two patients only. Neither early nor late radiation-associated complications were observed in any of the three hypoxyradiotherapy schedules during the follow-up period of 6ndash;105 months. Based on Kaplan-Meier analysis (median 48 months), a 5-year overall survival rate of approximately 61.5% and a local relapse-free survival rate of approximately 84.2% can be expected. Treatment failures were predominantly systemic.Conclusion: We believe it can be concluded that acute hypoxia has a radioprotective effect on normal tissues during accelerated hypoxyradiotherapy of colorectal carcinoma. Hypoxyradiotherapy permits safe administration of doses higher than those tolerated by normoxic, noncancerous tissue, resulting in the amplification of the biological effect of radiation on tumor tissue and contributing to an improved outcome after combined radiosurgical treatment of colorectal carcinoma.