Biomedical subjects
J Roberts
Publications and source records attributed to J Roberts.
How to critique qualitative research articles.
The critique of qualitative research requires the use of different standards and criteria than are used for quantitative research. The great diversity of available qualitative methods can make evaluation or critical appraisal difficult for consumers of research who are less familiar with these methods. The current paper suggests that the following guidelines be used when a qualitative research paper is being examined: the topic must be appropriate for qualitative enquiry; the specific qualitative research method chosen must "fit"; the literature reviewed should be consistent with the method chosen; there should be ample description of informants or participants, context, and researcher; appropriate methods for information gathering and information analysis should be employed; the conclusions should be sound; and, the research must have some importance and relevance.
RS-61443 for treatment-resistant human liver rejection.
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RS-61443: rescue therapy in refractory kidney transplant rejection.
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Fostering a change in policy. HIV, AIDS and the neuroscience nurse.
As new treatments and drug therapies enable the control of opportunistic diseases associated with Aids, its neurological manifestations are becoming more prevalent. This poses new challenges to neuroscience nurses, who must reassess their attitude to and understanding of the disease.
Transjugular intrahepatic portacaval stent shunts in patients with renal insufficiency.
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Hepatitis C and B in liver transplantation.
Hepatitis B recurrence remains a major problem facing liver transplantation programs. The risk of infection varies depending upon the HBV load. High doses of HBIg may reduce the risk of occurrence but it remains expensive. Finally, apparently new infections may occur posttransplantation, which may have been transmitted by organs or blood from HBsAg (-), HBcAb (+) donors, or may reflect reactivation of latent infections in patients who were HBsAg (-). HCV infections are common in patients undergoing liver transplantation, and HCV infection recurs in > 90% of patients; however, recurrent hepatitis C occurs in less than half of these patients. HCV is not an important cause of fulminant non-A, non-B hepatitis, but appears to be the most common cause of posttransplant hepatitis. So what is in the future? For hepatitis B, we still believe the efficacy of HBIg, and in which patients with hepatitis B HBIg should be used, remains to be defined. The effects of antivirals on posttransplant hepatitis B, as well as in prevention of HBV recurrence, also remain to be determined. In the United States, insurance companies are likely to play an important role in determining the future of transplantation for hepatitis B. Medicare recently excluded patients who were HBsAg (+) from coverage for liver transplantation, and a number of private insurers have subsequently followed suit. For HCV, newer screening tests for the virus are likely to decrease the rate of HCV acquisition following liver transplantation, from the current 35% incidence of HCV acquisition. The impact of antiviral treatment on posttransplant hepatitis remains to be determined and deserves study. Finally, the development of regimens that might allow prevention of recurrent HCV infections in patients undergoing liver transplantation also should be a matter of future study.
About turn in US on interferon alfa.
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Hepatitis B virus and apparent fulminant non-A, non-B hepatitis.
While there is evidence that hepatitis C virus (HCV) does not cause fulminant non-A, non-B hepatitis, the causal agent remains unknown. To evaluate the role of hepatitis B virus (HBV) in this disease, we used a two-step polymerase chain reaction (PCR) to amplify the surface and core regions of HBV DNA in serum and liver samples taken prospectively from twenty-six patients (mean age 36 years, range 1 to 64) with acute hepatic failure undergoing liver transplantation. HBV DNA was absent from the serum of all patients before transplantation. Seventeen patients were diagnosed as having non-A, non-B hepatitis because they lacked serological evidence of hepatitis A virus or HBV infection. Liver samples were taken from twelve of these patients, and six samples were positive for HBV DNA. By contrast HBV DNA was not detected in liver from three patients with acute liver failure caused by hepatitis A or toxins. HCV RNA was not found in pretransplant samples by PCR. Four of the six patients with detectable HBV DNA in liver and presumptive non-A, non-B hepatitis had detectable HBV DNA in serum after transplantation. One additional patient who did not donate pretransplant liver had HBV DNA in a post-transplant serum sample. Thus, HBV DNA was present before or after transplantation in seven of seventeen patients with apparent non-A, non-B hepatitis. Three of five patients with detectable post-transplant serum HBV DNA were serologically positive for HBV surface antigen. These findings indicate that HBV may be a common cause of fulminant hepatic failure in patients lacking serological evidence of HBV infection.
Structure of transcription elongation complexes in vivo.
The opening of duplex DNA in the elongation phase of transcription by Escherichia coli RNA polymerase in vivo was detected at a regulatory site where a prolonged pause in transcription occurs. Single-stranded DNA in the transcription bubble was identified by its reactivity with potassium permanganate (KMnO4). The elongation structure in vivo was similar to that of transcription complexes made in vitro with some differences. The observed reactivity to KMnO4 of the DNA template strand was consistent with the existence of an RNA-DNA hybrid of about 12 nucleotides.
Putamen volume reduction on magnetic resonance imaging exceeds caudate changes in mild Huntington's disease.
The characteristic pathological features of Huntington's disease (HD) are neostriatal atrophy and neuronal loss. Although neuroradiological studies often show caudate atrophy in patients with moderate HD, frequently no caudate atrophy is found early in the illness. There have been no quantitative reports to date on in vivo putamen volume measures in mild HD, although the structure is known to be neuropathologically involved in the illness. We measured volumes of caudate nucleus and putamen and bicaudate ratios (BCR) from magnetic resonance images, blind to diagnosis, in 15 patients with mild HD and 19 age- and sex-matched control subjects using a computerized image analysis system. The region showing greatest atrophy was the putamen, which was reduced 50.1% in mean volume in HD patients compared with control subjects (p less than 0.000001). In contrast, caudate volume was reduced 27.7% (p = 0.004). BCR was increased 28.5% in HD patients (p = 0.0002). Discriminant function analysis was 94% effective in identifying the diagnostic group based on putamen volume alone, whereas caudate measures had considerable overlap. Correction of putamen volume for head size led to 100% separation by group. Putamen measures and BCR correlated with neurological examination scores but caudate volume did not. Volumetric measurement of putamen is a more sensitive indicator of brain abnormalities in mild HD than measures of caudate atrophy.
Hepatitis C viral infection in liver transplant recipients.
In this study we examined multiple serial liver biopsy specimens from liver transplant recipients to determine the pathological features of hepatitis C virus-induced hepatitis. Hepatitis C virus infections acquired after transplantation and previous infections that recurred in patients after transplantation were confirmed by the results of the polymerase chain reaction. Of 43 patients infected with the hepatitis C virus, 18 had a mild form of chronic hepatitis. Four patients had hepatitis that progressed to focal bridging fibrosis or cirrhosis. There were no significant clinical or pathological differences between infections acquired after transplantation and recurrent infections (as determined by polymerase chain reaction) except that acquired infections more often developed into hepatitis. Findings indicative of hepatitis C infection included portal and parenchymal mononuclear infiltrates of varying degrees, acidophilic necrosis and swollen hepatocytes. Other common findings included lymphoid aggregates, bile duct damage and fatty change. Atypical pathological conditions included extensive hepatocyte swelling or acidophilic necrosis with minimal inflammation mimicking ischemia and ductal or ductular damage and proliferation with mixed portal infiltrates mimicking rejection or obstruction. We conclude that in transplant recipients infection by the hepatitis C virus usually produces a mild disease state, but the diagnosis of hepatitis can be difficult to make because indicators of hepatitis may mimic those of rejection, ischemia, obstruction or other hepatic infections. Serial biopsy specimens with persistent pathology and polymerase chain reaction may be necessary to define the presence of a hepatitis C virus lesion.
Incidence and diagnostic features of macroregenerative nodules vs. small hepatocellular carcinoma in cirrhotic livers.
In Japan, the presence of a large regenerative nodule within a cirrhotic liver, referred to as a macroregenerative nodule or adenomatous hyperplasia, is thought to play a role in the pathogenesis of hepatocellular carcinoma. These lesions, however, have received little attention outside of Japan. We examined 110 sequentially explanted cirrhotic livers for the presence of such nodules. By gross examination, 19 livers (17.3%) had 40 nodules (10 livers had more than one nodule) between 0.8 and 3.5 cm in diameter. By histological examination, 28 of these were macroregenerative nodules and 12 were hepatocellular carcinomas. Three of these hepatocellular carcinomas, however, appeared to have arisen in association with a macroregenerative nodule. We found that the architectural features of thickened cell plates, formation of trabeculae and loss of reticulin were usually very helpful in differentiating benign macroregenerative nodules from hepatocellular carcinoma. The incidence of macroregenerative nodules in our series was similar to that seen in the Japanese studies, and although we feel that they may play a role in the pathogenesis of carcinoma, we do not believe their presence is necessary for the development of hepatocellular carcinoma.
Prospective, randomized trial of inpatient vs. outpatient bowel preparation for elective colorectal surgery.
A prospective, randomized trial of inpatient vs. outpatient bowel preparation for elective colorectal surgery was performed in 100 consecutive patients. Bowel preparation was standardized for both groups and consisted of 4 liters of Colyte (Reed & Carnrick, Piscataway, NJ) and oral neomycin and Flagyl (G. D. Searle & Co., Skokie, IL) the day before surgery. Patients were randomized into four subcategories: ileocolostomy, colocolostomy, abdominal perineal resection, and other. Tap water enemas were administered on the morning of surgery to ensure and adequate mechanical preparation. Ninety-six percent of the inpatient group and 97 percent of the outpatient group were able to drink three-fourths or more of the oral lavage preparation (P = 0.789, Fisher's exact text). A mean of 2.26 tap water enemas was required to achieve clear returns for the inpatient group, compared with 2.28 tap water enemas for the outpatient group (P = 0.221, Fisher's exact test). The adequacy of the bowel preparation as graded by the primary surgeon was good (84 percent), fair (12 percent), and poor (4 percent) in the outpatient group (P = 0.673, Fisher's exact test). Wound infection developed in 4 percent of the inpatient group and 4 percent of the outpatient group (P = 1.0, Fisher's exact test). Anastomotic leak of intra-abdominal abscess was seen in one patient in each group (P = 1.0, Fisher's exact test). We conclude that outpatient bowel preparation is as effective as inpatient bowel preparation for elective colorectal surgery and offers the advantage of cost savings and shorter hospitalization.
Streptococcal gangrene presenting as hip pain: two case reports and review of the literature.
Two cases of streptococcal gangrene are reported. Both patients, with hip pain and no obvious source of infection, presented to the same orthopaedic team within a few days. After initial treatment with NSAIDs the outcome was fatal in the cases described. A review of the literature revealed that the administration of NSAIDs may accelerate the course of the disease. The authors conclude that this very rare cause of arthralgia and malaise should be excluded before the administration of NSAIDs for such complaints.
Withdrawal from chronic phencyclidine produces a pentylenetetrazol-like discriminative stimulus.
Rats trained to discriminate the anxiogenic compound pentylenetetrazol (PTZ) from water were implanted with osmotic mini-pumps containing 7 mg/kg/day phencyclidine (PCP) or water. Rats were tested for generalization to PTZ 24 hours prior to pump removal, and 4 to 96 hours after pump removal. While the pumps were in place, rats did not generalize to PTZ. When the pumps were removed on day 10, rats in the water group did not generalize to PTZ, but 69% of the rats in the chronic PCP group responded on the PTZ lever at 4 and/or 24 hours after pump removal, suggesting that the PCP withdrawal state mimics the interoceptive cue produced by PTZ. This withdrawal phenomenon was repeatable, in that rats that generalized once to PTZ during PCP withdrawal, generalized a second time when the procedure was repeated. In addition, the phenomenon was dose-dependent, as rats that did not generalize to PTZ after 7 mg/kg/day PCP did generalize when the chronic dose of PCP was increased to 10 mg/kg/day. These findings suggest that there is an anxiogenic component of PCP withdrawal and that tolerance does not develop to this effect.