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Biomedical subjects

W Rogers

Publications and source records attributed to W Rogers.

At least 91 records · Page 5Linked to original sources

Limitations of polyethylene glycol precipitation assays for circulating immune complexes.

Polyethylene glycol precipitation assays (PEG-A) have been promoted as technically simple, inexpensive methods for detecting and quantitating circulating immune complexes; however, their specificity and sensitivity have not been clearly defined. Data are presented showing that the percent recovery of IgG in 3.5% PEG increases as the concentration of IgG increases such that hypergammaglobulinemia alone can cause a positive test result. When sera from 25 patients with rheumatoid arthritis were studied, no correlations were found between results obtained by either Raji cell assay, or cryoprecipitation and those obtained by PEG-A. We conclude that 3.5% PEG-A, although appealing because of simplicity, can not be used as a substitute for established, but technically more demanding assays for circulating immune complexes.

Antigen-Antibody Complex↗

Total parenteral nutrition for maintenance of growth, carcass mass and positive nitrogen balance in rats with a small transplantable tumor.

This study evaluates the effects of 13 days of total parenteral nutrition (TPN) on body weight, carcass mass and nitrogen balance in rats with and without a transplanted Morris No. 7777 hepatoma. Groups of rats without a tumor as well as rats with a tumor of about 3% of body weight or less were shown to maintain carcass weight as well as maintain a positive nitrogen balance when fed totally by vein. The present experiment was done under the same conditions as a previously reported experiment except that the size of the tumor in the rats was considerably smaller. These past studies showed that as the hepatoma gets much larger than 3% of the body weight, it was inhibitory to carcass weight gain even when the rats were given TPN. Thus, the size of the tumor influences the ability of TPN to sustain carcass weight.

Animals↗

Sonographic anatomy of the hepatic artery.

One hundred clinical abdominal sonographic examinations were assessed to determine the frequency with which various parts of the hepatic artery system were imaged. The common, proper, and right hepatic arteries were seen in a large percentage of cases (92%, 75%, and 73%, respectively). Sixty-one consecutive patients with dilated biliary ducts were evaluated to determine the relationship of hepatic artery branches to the biliary tree and portal venous system. Normal and variant hepatic artery anatomy is discussed. Knowledge of the hepatic artery system and its variations is useful in the sonographic assessment of problems involving the gallbladder, liver, pancreas, and portal venous system.

Bile Duct Diseases↗

Resin hemoperfusion in ethychlorvynol overdose.

An 18-yr-old male with a severe ethchlorvynol (ECV) overdose was treated with Amberlite XAD-4 resin hemoperfusion. Plasma ECV concentration declined 33% during a 3.5-hr hemoperfusion, but rebounded substantially, peaking 6 hr later. It was estimated that 16% of ECV in the body was removed. Following hemoperfusion, plasma ECV concentrations declined linearly at a rate of 13 mg/1/day. Hemoperfusion clearance was estimated by both the traditional method, using extraction ratios across the column and column blood flow (Cl = 270 ml/min), and an alternative method, using blood concentrations during hemoperfusion and recovery of drug from the resin (Cl = 184 ml/min). The latter may provide a better estimate of hemoperfusion clearance because it is not subject to error (which can be substantial) in measurement of column blood flow. The resin completely extracted ECV from plasma, resulting in a rate of elimination 10 times that expected from endogenous processes. To aid in kinetic analysis, blood:plasma partition and protein binding of ECV in 3 normal subjects were also examined. Blood:plasma ratio averaged 0.88 +/- 0.04 and fraction free in plasma, 0.38 +/- 0.02; neither changed as a function of blood concentration between 27 and 108 mg/1. Our data indicate that removal of ECV from the overdosed patient by hemoperfusion is limited by extensive distribution in and slow redistribution from body tissues, but because of the extremely slow rate of removal by the body and the severe nature of the ECV overdose, Amberlite XAD-4 hemoperfusion may be clinically useful.

Adolescent↗

CT of inflammatory disease of the psoas muscle.

Computed tomography (CT) findings in eight cases of psoas inflammatory disease are described retrospectively. Because of its exquisite retroperitoneal imaging capabilities, CT proved to be an ideal tool in evaluating suspected disease in this area. Clinically, the deep position of psoas abscesses has made diagnosis problematic. In addition, many radiographic signs of psoas inflammation have provided only indirect evidence, such as displacement of the ureter or alteration of the psoas margin. The organ-specific information available with CT makes detection more efficient and diagnosis more certain. Especially when coupled with percutaneous aspiration biopsy, CT has proved an effective and rapid means of diagnosing and guiding the therapy of psoas abscess.

Abscess↗

Autotransfusion: intraoperative use in ruptured ectopic pregnancy.

Autotransfusion was used in 38 patients with ruptured ectopic pregnancy. There was no mortality in this series. Transfusion-related morbidity occurred in six patients; two developed clinical coagulopathy; two, pulmonary edema; and two had minor transfusion reactions to concomitantly used banked blood. The procedure is safe and efficient and represents less risk to the patient than does the use of banked blood. The savings of the large amount of banked blood is certainly in keeping with a more salutary use of this valuable resource.

Blood Transfusion, Autologous↗

Cardiovascular effects of intravenous delta-9-tetrahydrocannabinol: autonomic nervous mechanisms.

The contribution of autonomic nervous system activity to the cardiovascular effects of delta-9-tetrahydrocannabinol (THC) was evaluated in 4 normal subjects. The peak heart rate rise after THC was attenuated by atropine and by propranolol, and nearly abolished by atropine-propranolol pretreatment. Blocking drugs also attenuated THC-induced changes in forearm blood flow and vascular resistance but did not affect changes in fingertip temperature. The data suggest that THC acts to induce sympathetic stimulation and parasympathetic inhibition of cardiovascular control pathways. Cardiovascular responses in an additional subject who developed hypertension after either intravenous or smoked marijuana are described.

Adult↗

Computer-aided medical diagnosis: literature review.

The difficulty of the medical diagnostic task and the advantages of the computer as an aid in this task are discussed. The general strategy and structure of any computer-aided system is presented, and the relationship of diagnostic accuracy to key variables involved in the development, test and use of a computer-aided diagnostic system is examined. These variables include: the computer algorithm, the source of the information used to develop the data base, the number and type of diseases under investigation, the number and type of indicants used, the source of the test sample, and the source of the validated diagnosis. A table of 58 empirically tested computer-aided medical diagnostic systems is presented; each system is summarised in relation to the variables mentioned above and diagnostic accuracy.

Clinical Laboratory Techniques↗

Excretion pathways of amphotericin B.

The role of the biliary system in excretion of amphotericin B was explored in a dog model that allowed either external diversion of all bile or complete biliary obstruction. In dogs with biliary diversion, which were given a single dose of amphotericin B intravenously, excretion of amphotericin B in the bile lasted for seven to 10 days and accounted for only 3% +/- 2% (mean +/- SD) of the dose, whereas excretion in the urine was prolonged (23--35 days) and greater (21% +/- 5% of the dose); the stool contained no amphotericin B. However, bile salt depletion may have depressed biliary excretion of amphotericin B: in a dog with an intact biliary system, 19% of the dose was excreted in the stool over 11 days. In dogs given amphotericin B daily, serum levels were 19% +/- 3% higher during periods of biliary obstruction than during periods of free bile flow (P less than 0.05). Thus, excretion of amphotericin B in the bile (less than or equal to 19% of the dose) and in the urine (21% of the dose) accounted for a minority of total drug clearance. Nevertheless, prolonged excretion of amphotericin B by these routes after a single dose suggests that infrequent doses of amphotericin B may provide effective treatment for certain forms of fungal infection.

Amphotericin B↗

Tumor-host responses to various nutritional feeding procedures in rats.

Parenteral and enteral nutrition are being used as adjuncts to cancer therapy. A liquid diet formulation containing a 27% solution of glucose and 3.9% crystalline amino acids with electrolytes and vitamins was given continuously for a week via parenteral (iv), and via intragastric (ig) routes and also was given ad libitum via the oral or per os (po) route to groups of Buffalo rats with and without a Morris No. 7777 transplantable hepatoma to find out how these feeding procedures affect tumor-host interactions. Other groups of rats with and without the hepatoma were given solid food ad libitum. The following parameters were examined: mortality, carcass and organ weights, body and tumor growth, nitrogen balance, energy intake, fluid balance, urinalysis, hematology values, and serum protein levels. The results are considered with respect to the influence of the tumor on the host and the influence of the feeding procedure on the animal with and without a tumor. The presence of the hepatoma was associated with: higher mortality, a decrease in carcass mass, leucocytosis, anemia, a decrease in serum IgG, transferrin and albumin, and an increase in serum alpha fetoprotein. The iv and ig feeding procedures alone resulted in some mortality which was exacerbated by the presence of the tumor. Mortality was especially high in the tumorous rats on the ig feeding procedure. The degree of positive nitrogen balance and carcass mass was similar in non-tumorous rats fed the same liquid diet formula when given iv, ig, or po. Tumorous rats fed the liquid diet ad libitum showed anorexia and a significantly lower nitrogen balance. The iv and ig feeding of tumorous rats at a level which was well above those of the tumorous rats given solid or liquid diet ad libitum maintained the same degree of positive nitrogen balance as non-tumorous rats. Even though the iv feeding of tumorous rats maintained about the same degree of positive nitrogen balance as non-tumorous rats, these tumorous rats still suffered loss of carcass mass. It appears that the large rapidly growing hepatoma has priority for available nutrition over the host. It is further suggested that the rapidly growing hepatoma places an ever increasing demand on the available nutrients. Thus, a point is eventually reached where even supplemental nutritional support can no longer meet the needs of the growing hepatoma and the host.

Animals↗

Gray-scale ultrasonography of hepatic amoebic abscesses.

Retrospective analysis of the ultrasonograms of 42 hepatic amoebic abscesses in 34 patients was performed. All lesions were less echogenic than normal liver. All but 1 were contiguous with the liver capsule and had slight distal sonic enhancement. Twenty-three were predominantly homogeneous with fine, low-level echoes. This pattern is highly suggestive of hepatic amoebic abscess. Nineteen abscesses did not show this pattern and could not be diagnosed based on ultrasonographic criteria.

Humans↗

Total parenteral nutrition and inhibition of gluconeogenesis on tumor-host responses.

Rats bearing the Morris hepatoma No. 7777 were randomized into three treatment groups. Two of the groups received a nutritionally complete liquid formula diet per os ad libitum. One of these two groups received hydrazine sulfate (HS; an inhibitor of gluconeogenesis) twice daily (15 mg/kg) for 5 days. A third group of tumorous rats received the HS therapy and was given the liquid diet parenterally for 5 days. Tumorous rats fed per os, especially with HS therapy demonstrated inhibition of tumor growth, reduction of body and carcass weight, anorexia and decreased nitrogen retention. The combination of parenteral feeding and HS therapy sustained body and carcass weight with high nitrogen retention but stimulated tumor growth and was associated with liver toxicity. These results support the concept that cancer cachexia involves 'a systemic energy-losing cycle dependent on an interplay of tumor glycolysis and gluconeogenesis'.

Animals↗