N-acetylcysteine prophylaxis significantly reduces the risk of radiocontrast-induced nephropathy: comprehensive meta-analysis.

The objectives of this study was to assess the overall effect of N-acetylcysteine (NAC) in preventing radiocontrast-induced nephropathy (RCIN) using all available data in the literature. RCIN is associated with increased morbidity and mortality. Existing randomized trials of NAC are small and show inconsistent results. Prior meta-analyses do not include data from the most current studies. We used standard search protocols to identify all published articles and abstracts of prospective trials using NAC with fluid hydration compared to hydration alone in patients with chronic renal insufficiency undergoing contrast procedures. A rise in serum creatinine by 0.5 mg/dl or 25% above baseline at 48-72 hr after contrast exposure was used as the primary outcome. We identified 14 trials of NAC with 1,584 patients published as full-text articles. Using a random-effects model, the use of oral NAC resulted in a significant reduction in the risk for developing RCIN (RR = 0.57; 95% CI = 0.37-0.84; P = 0.01). This finding did not significantly change in a fixed-effect model (RR = 0.55; 95% CI = 0.42-0.73) or when the data were reanalyzed using only randomized trials in all forms (i.e., articles and abstracts; RR = 0.67; 95% CI = 0.47-0.95). We identified only one important difference between the positive and the negative studies: the cumulative exposure to contrast media (174 vs. 152 ml). Metaregression did not show a significant relationship between contrast volume and the RR of developing RCIN (P > 0.10). In the trials showing benefit for NAC, the treated patients' postprocedure creatinine unexpectedly decreased by 0.21 mg/dl (95% CI = 0.33-0.08). Prophylaxis with NAC significantly reduces the risk for RCIN. The reasons for improvement in serum creatinine in patients treated with NAC are unclear, but may include improved renal blood flow due to NAC and/or vigorous hydration.     

The nucleotide: DNA sequencing and its clinical application.

Information determining cellular structure and function is contained in chromosomal DNA. Genes, regions of DNA encoding this information, are composed of specific sequences of nucleotides. DNA sequencing methods have been developed to identify these sequences. Even subtle alteration (or mutation) of these sequences can lead to many human syndromes and diseases. This article reviews 1) the structure of the nucleotide, 2) the methods of DNA sequencing, and 3) its recent clinical application in analysis of the nevoid basal cell carcinoma syndrome.     

A randomized trial of two types of adjuvant chemotherapy in radiotherapy-treated patients with clinical stages I and II high-grade non-Hodgkin's lymphoma

Summary This paper reports the 8-year results of comparing the use of two types of adjuvant chemotherapy following involved field radiotherapy for clinical stages I and II high-grade non-Hodgkin's lymphoma. Twenty-four patients received 6 weeks of VAP plus 2 years of oral maintenance chemotherapy, and 30 had six cycles of CMOPP. Four patients were not in complete remission at completion of i. v. chemotherapy (CR rate 91%). Ten patients (18.5%) have relapsed (VAP/M=5; CMOPP=5), with only two of these remaining alive, both of them being disease free. There have been three deaths from intercurrent causes, one from malignant melanoma and the other two from myocardial infarction. The relapse-free survivals at 2, 5 and 8 years were 80%, 76% & 76% respectively. The overall survivals at the same time points were 86%, 72% & 68%. There were no significant differences in either relapse-free or overall survival for either of the two treatment groups. The shorter period of weekly intravenous chemotherapy (VAP/M) was better tolerated than 36 weeks of CMOPP, and the former appears to produce equivalent results.     

Enhanced Reliability and Renewed Applications of the Deltopectoral Flap in Head and Neck Reconstruction

Bakamjian introduced the deltopectoral skin flap in 1965, and thereafter it was used extensively for reconstructive surgery of the head and neck. Flap failure rates of 10% to 25% were reported, necessitating the development of alternative methods of reconstruction and eventually relegating the flap to historical references. Since 1991, we have used the deltopectoral flap in 24 patients for reconstruction after head and neck tumor surgery. Simple technical modifications have been used to enhance the reliability of this flap, with no observed failures or even partial flap loss. The deltopectoral flap remains a versatile and reliable tissue source that can be used simultaneously with the pectoralis major myocutaneous flap for a variety of complex head and neck reconstructions. Laryngoscope, 106:1230-1233, 1996     

GluR1 and GluR2/3 subunits of the AMPA‐type glutamate receptor are associated with particular types of neurone in laminae I–III of the spinal dorsal horn of the rat

GluR1 and GluR2 subunits of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor are expressed at high levels by neurones in laminae I–III of rat spinal dorsal horn, an area which contains numerous, densely packed small neurones. In order to determine whether these subunits are expressed by inhibitory or excitatory neurones, we combined pre-embedding immunocytochemistry with antibodies that recognize either GluR1, or an epitope common to GluR2 and 3, with postembedding detection of γ-aminobutyric acid (GABA) and glycine. Most (78%) of the neurones with GluR1-immunoreactivity were GABA-immunoreactive, and some of these were also glycine-immunoreactive, whereas nearly all (97%) of the GluR2/3-immunoreactive neurones were not GABA- or glycine-immunoreactive. We carried out double-immunofluorescence and confocal microscopy to provide further information on the neurochemistry of cells that express these subunits. As expected, all neurotensin- and virtually all somatostatin-immunoreactive cells (which are thought to be excitatory interneurones) were GluR2/3- but not GluR1-immunoreactive, whereas parvalbumin-containing cells (most of which are GABAergic) possessed GluR1-, but usually not GluR2/3-immunoreactivity. Neurones that contained nitric oxide synthase (most of which are GABAergic) were more variable, with 57% GluR1-immunoreactive and 41% GluR2/3-immunoreactive. Cholinergic neurones in lamina III (which are also GABAergic) invariably showed each type of GluR-immunoreactivity. These results suggest that neuronal populations in laminae I–III have characteristic patterns of GluR expression: GluR1 is particularly associated with inhibitory neurones, and GluR2 with excitatory neurones. This makes it likely that some of the AMPA receptors present on the inhibitory interneurones lack the GluR2 subunit, and may therefore have significant Ca²⁺-permeability.