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Biomedical subjects

C Marsh

Publications and source records attributed to C Marsh.

44 records · Page 3Linked to original sources

Detection of blood group antigens in frozen sections of prostatic epithelium.

The detection of blood group antigens (BGA) in non-malignant prostates by previous workers has been at best inconsistent. BGA have not before been detected in prostatic carcinomas. In this preliminary study, a variety of anti-BGA reagents, with known specificities that involve the carbohydrate backbone in addition to the BGA specific terminal monosaccharides, were used to study the expression of the A and H (O) BGA in cryostat sections of 16 patients with benign prostatic disease and nine with prostatic cancer. Positive staining, appropriate to the patients' blood group, was seen in all of the benign tissues when anti-BGA reagents that included specificity against type 2 backbone structures were used. Staining was absent, however, if the reagent had only type 1 specificity. The anti-A and anti-H (O) reagents which gave the best staining patterns in benign tissues were used in malignant tissues. No cancer was found to express A antigen but eight of the nine prostatic cancers were positive for the H (O) antigen irrespective of blood group. Using fresh frozen material and appropriate reagents, BGA may be reproducibly detected in the epithelium of all non-malignant prostates, suggesting that a significant component of BGA is probably lipid-based on type 2 carbohydrate backbone chains. Further studies of changes in BGA expression in prostatic cancer are warranted.

ABO Blood-Group System↗

Precision of dual photon absorptiometry measurements.

One of the important uses of bone absorptiometry is to examine the rate of bone mineral change in order to evaluate therapy and to identify individuals who need therapy. Generally, this involves comparing the difference between two scans obtained months to years apart. This study investigates the precision of dual photon absorptiometry using a human torso phantom, normal subjects, and abnormal patients. These studies showed that bone mineral calculated as g/cm2 was more precise than g/cm. Reanalysis of the same scan by the same individual produced an average error equivalent to that produced by scanning and analyzing the same subject on multiple occasions. Interobserver analysis error was essentially equal to the intraobserver error. In order to obtain maximum precision, care must be taken that the integrated area of a repeat scan is identical to the previous scan. Our findings indicate that to be confident (95%) of a real change between two scans a difference of at least 5.6% must be measured.

Bone and Bones↗

Epidermal-growth-factor receptors in human bladder cancer: comparison of invasive and superficial tumours.

The presence of epidermal-growth-factor (EGF) receptors in normal and neoplastic human urothelium was studied in 12 control patients and in 48 patients with transitional cell carcinoma of the bladder, 24 with invasive (pT3) and 24 with superficial tumours (9 pT1, 15 pTa). EGF receptors were identified on frozen sections by means of an indirect immunoperoxidase technique with a monoclonal antibody against the EGF receptor. Significantly more invasive tumours (21 of 24) than superficial (7 of 24) were stained positively for the EGF receptor (X2 = 14.49; p less than 0.001). Significantly more poorly differentiated tumours (18 of 21) than moderately differentiated tumours (10 of 27) were EGF-receptor positive (X2 = 9.6; p less than 0.01). No control sample stained positively for the EGF receptor. These findings suggest that the presence of a high intensity of staining for the EGF receptor in human bladder tumours is associated with poor differentiation and with invasion.

Adult↗

Bone and muscle atrophy with suspension of the rat.

A modification of the Morey tail suspension model was used to determine atrophic responses of rat bone and muscle with 14-90 days unloading of the hindlimbs. Bone uptake of methylene diphosphonate followed a phasic pattern similar to changes in bone formation rate in immobilized dogs and rats. Increased uptake at 60 days (P = 0.01, femur) indicated an increased bone metabolism. Regional densitometry demonstrated a preferential loss of bone mineral in the trabecular mass (P = 0.02) at 30 days and in the cortical shaft by 90 days (P = 0.03). Maximal muscle atrophy occurred within 14-30 days. The gastrocnemius was less severely affected by suspension than by immobilization techniques, whereas the soleus atrophied (by weight) similarly, suggesting that muscle atrophy in the suspension model is distinctly different from immobilization atrophy. One significant response of skeletal muscle to suspension was an altered blood distribution. Muscle blood distribution changes reflect the hypodynamic state of muscle that continues to contract but probably at an altered rate in response to altered functional demands.

Animals↗

Pharmacist monitoring of parenteral nutrition: clinical and cost effectiveness.

The effect of pharmacist involvement in total parenteral nutrient (TPN) therapy on patient outcome and cost of therapy was studied. Data from 26 patients who received standard TPN solutions without pharmacist monitoring (Group 1) were compared with those from 26 patients whose TPN therapy was individualized (by use of a minicomputer) and monitored by a pharmacist (Group 2). Six patients from each group who were 35 days of age or younger and who received TPN as the only caloric source for 8 to 20 days were compared for clinical response. Mean duration of TPN therapy increased form 12.3 +/- 9 days for Group 1 to 14.8 +/- 12 days for Group 2, and the TPN use rate for Group 2 was 31% above that for group 1. The mean daily charge for TPN was greater for Group 1 ($72.00) than for Group 2 ($50.18). The pharmacy's mean cost per course of TPN for Group 2 was $44.10 less than that for Group 1. The mean weight gain in Group 1 was significantly less (4 g/day) than that in Group 2 (17 g/day) (p less than 0.05) (for the six patients per group compared). Pharmacist monitoring of TPN reduced the pharmacy's costs and patient charges for TPN and improved the patients' clinical responses to TPN.

Child, Preschool↗

Relaxation times of normal and atrophied muscle.

Magnetic resonance imaging is being used to investigate physiological changes induced by microgravity. Using human (bed rest) and animal (tail suspension) models simulating zero gravity, muscle atrophy was studied. Despite significant physiological changes in muscle mass, distribution of blood flow, and muscle water, no changes in muscle proton relaxation times were found at several different resonant frequencies (6, 10, 20, and 200 MHz). These results suggest that observed changes in relaxation times as reported in pathologic studies are likely due to the pathological changes and not the accompanying muscle atrophy.

Animals↗

Identification and characterization of species of the family Bacteriodaceae by polyacrylamide gel electrophoresis.

Polyacrylamide gel electrophoresis was used to compare protein profiles of members of the family Bacteriodacceae. Cell-free extracts were prepared and the protein components separated by multistage polyacrylamide gel electrophoresis. The profiles were distinct and reproducible thus allowing identification of species, subspecies, and minor strain differences. Lyophilization of the cell-free extracts did not alter the major protein components. The results indicate that the techniques used may be useful in conjunction with conventional tests in identification at the species level.

Bacteroidaceae↗