Biomedical subjects
D T Rowlands
Publications and source records attributed to D T Rowlands.
Argyrophilic nucleolar organizer regions in breast carcinoma. Correlation with DNA flow cytometry, histopathology, and lymph node status.
Argyrophilic nucleolar organizer regions (AgNOR) have been correlated with proliferative activity of neoplasms. Increased AgNOR may reflect increased proliferative activity of cells or ploidy. To explore this hypothesis, 41 breast carcinomas were processed for AgNOR silver staining and DNA flow cytometry. AgNOR counts were expressed as mean AgNOR/nucleus and percentage of tumor cells with more than five AgNOR/nucleus. The first count was designated mean AgNOR or mAgNOR, and the second count was designated AgNOR proliferative index or pAgNOR. Using Mantel-Haensel statistical analysis, carcinomas that exhibited mAgNOR of 2.4 or more had a high likelihood of aneuploidy (P less than 0.0001), an S-phase fraction of more than 5.8% (P less than 0.003), or a diameter greater than 2 cm (P less than 0.007). In addition, tumors with pAgNOR of 8% or more showed a statistically significant correlation with aneuploidy (P less than 0.004), tumor grade (P less than 0.04), and a more significant one with high S-phase fraction (P less than 0.0001). No significant correlation was obtained between pAgNOR and tumor size or lymph node status. These data indicate that AgNOR quantitation reflects changes in DNA ploidy and cell proliferation. They also suggest that the mean AgNOR counts correlate best with the DNA mass or ploidy and that the frequency of cells with higher AgNOR count best reflects proliferative activity or S-phase fraction.
Autopsies should be required in tissue donation.
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Argyrophilic nucleolar organizer regions in Wilms' tumors and related lesions: a histologic and chromosomal correlation.
The argyrophilic nucleolar organizer regions (AgNORs) have been extensively investigated in different neoplasms, and their increased number has been frequently linked to aggressive tumor behavior. To evaluate this association, 22 specimens from 21 patients with Wilms' tumors and related lesions were stained by the AgNOR silver-staining technique in formalin-fixed, paraffin-embedded tissue. The aim of the study was to assess the significance of AgNOR count independently or in relation to histology in predicting the behavior of these neoplasms. Eleven nonneoplastic pediatric kidneys were used as controls. The controls had a range of 1.55 to 2.26 AgNOR/nucleus with a mean +/- SD of 1.91 +/- 0.22. The tumors showed a range of 1.25 to 2.86 AgNOR/nucleus with a mean +/- SD of 2.10 +/- 0.38 with obvious overlap between tumors and controls. The two unfavorable histology Wilms' tumors and the malignant rhabdoid tumor showed no increase in the number of AgNOR (1.66, 2.04, and 2.05, respectively). We further quantitated the nucleolar organizer regions (NOR) in metaphase spreads of three of the neoplasms, compared those with the patients' peripheral blood, and showed no difference in NOR numbers except for an occasional decrease in G-group NORs in the tumor cells. Tumors that had metaphase NOR counts of 6 to 9/nucleus had a mean interphase AgNOR count of less than 2.5. These results suggest that quantitative analysis of AgNORs in Wilms' tumors and related lesions is not a reliable predictor of aggressive tumor behavior. The discrepancy between metaphase and interphase NOR counts indicates that AgNOR counts are merely the reflection of the spatial arrangement of NOR-bearing chromosomes.
Multiparametric analysis of peripheral blood in the normal pediatric population by flow cytometry.
Lymphocyte subset analysis was performed on 114 healthy children and 84 healthy adults. Samples were prepared by a whole blood lysis technique and analyzed by flow cytometry. The percentage and total number of CD3+, CD4+, CD8+, and CD19+ lymphocytes were calculated for each of six age groups. A direct correlation with age was seen in the percentages of CD3+, CD4+, and CD8+ lymphocytes. The absolute number and percentage of total lymphocytes, the percentage and absolute number of CD19+ lymphocytes, and the absolute number of CD3+ lymphocytes decreased with age. No significant correlation with age was observed for white blood cells, the absolute number of CD4+ and CD8+ lymphocytes, and the CD4+/CD8+ ratio.
Concurrent use of the oxfendazole pulse release bolus and the monensin rumen delivery device in young grazing cattle.
When they were turned out to grass in May 1987 for their first season, 10 calves were dosed with a 5 x 750 mg oxfendazole pulse release bolus (OPRB) and a monensin sodium rumen delivery device (RDD); eight calves received one OPRB; 10 calves received one RDD and eight calves received neither bolus. Each group was set-stocked on individual paddocks which had been grazed during the previous season by cattle which developed clinical parasitic gastroenteritis and bronchitis (husk). In July, before they were due to be moved to new pastures in mid-summer, and before they were dosed strategically with levamisole HCl, some of the calves not dosed with an OPRB succumbed to clinical parasitic gastroenteritis and husk and received emergency anthelmintic treatment, after which no further clinical episodes occurred. The 'dose and move' strategy was implemented in early August after which both groups not dosed with an OPRB were set-stocked together until the trial ended on October 14, 147 days after turn out. The two groups of calves which had received the OPRB were also moved to new pasture and set-stocked together until the end of the trial. No evidence of clinical helminthiases developed in either of the two groups of calves dosed with OPRBs and their faecal worm egg and larval counts, and plasma pepsinogen activities remained low. They gained significantly more weight than the two groups of calves not dosed with OPRBs (P less than 0.001). The bolus types were compatible and induced no untoward side-effects when used together.
Control of naturally acquired bovine parasitic bronchitis and gastroenteritis with an oxfendazole pulse release device.
Four groups, each of six male Friesian calves, were set-stocked on separate 0.66 ha paddocks from May 7 until October 23 1986. Each of the animals in groups 1 and 4 was dosed with an oxfendazole pulse release bolus at turn out whereas the animals in groups 2 and 3 were left untreated. Parasite-free naive tracer calves were introduced into each paddock for a limited period 12 days after turn out and again at the end of the trial. No adverse reactions or clinical signs were observed in either of the groups of calves which received boluses. The development of clinical parasitic gastroenteritis in both the untreated groups necessitated the humane slaughter of two animals and emergency anthelmintic treatment of the remainder. The lower plasma pepsinogen concentrations, and lower faecal egg and larval counts and worm burdens post mortem, together with the absence of clinical signs of parasitic gastroenteritis and bronchitis in the treated calves, confirmed the high efficacy of the bolus treatment.
The oxfendazole pulse release bolus.
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Mononuclear cell phenotyping in a hemodialysis population.
A study of peripheral blood mononuclear cell phenotyping and HIV testing was performed in 39 chronic hemodialysis patients. The following abnormalities were found in comparison to a control population: 1) a lower percentage of lymphocytes in the white blood cell differential count, 2) a lower percentage of total T cells, 3) a lower percentage and absolute number of suppressor T cells and 4) a lower percentage and absolute number of B cells. Both increasing age and blood transfusions were associated with reduced helper cells.
Intracellular processes in immunity.
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The ability of diamphenethide to control immature Fasciola hepatica in sheep at a lower than standard dose level.
Groups of eight Welsh Mountain sheep were dosed with diamphenethide at the rate of 70 mg/kg bodyweight at either one, four, six or eight weeks after artificial infection with approximately 300 Fasciola hepatica metacercariae. Comparisons were made with similarly infected but undosed sheep and with sheep which were neither infected nor dosed. The good clearance of flukes up to six weeks of age (above 97 per cent on pooled data) was reflected in the plasma concentrations of the accepted liver damage marker enzymes glutamate dehydrogenase and gamma-glutamyl transpeptidase. Highly significant correlations were demonstrated between the numbers of flukes recovered, the plasma levels of these enzymes and haemoglobin and plasma albumin values. At 70 mg/kg, diamphenethide was shown to be able to control F hepatica populations of up to six weeks of age. The systematic use of diamphenethide at this dose level at intervals of up to six weeks during the period of metacercarial challenge should prevent ovine fascioliasis.
Changes in membrane markers and chromosome patterns in chronic T-cell leukemia.
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HLA and disease susceptibility.
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Lymphocyte subpopulations in human disease.
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Studies of the modified venous allograft.
Segments of rat inferior vena cava were modified by proteolytic digestion and dialdehyde starch tanning in an attempt to alter their antigenic nature and increase their tensile strength. These tissues were found to retain their ability to sensitize allogeneic recipients in both the intradermal and intra-aortic positions in all 50 experimental animals. Furthermore, these grafts had a very high aneurysm formation (100%), and aneurysm rupture (54%) rate even in isogeneic recipients, suggesting that the modification procedure so damages the structural integrity of venous tissue that its use in clinical situations may have disastrous consequences. Histologic evidence of intimal thickening, elastic disruption, and often severe acute and chronic inflammation supported the gross evidence of mechanical and immunologic damage and suggests that a mild brief course of immunosuppression may be indicated in clinical trials in situation in which autogenous saphenous vein in unavailable. Although the use of prosthetic mesh support for the graft may help to avoid structural changes, the introduction of synthetic materials may offset the theoretical advantages of the venous tissue.
Lymphocyte studies in asymptomatic cigarette smokers. A comparison between lung and peripheral blood.
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Levamisole: anthelmintic activity in calves following dermal application.
A series of seven experiments designed to evaluate the anthelmintic efficacy of levamisole (1-tetramisole) by dermal application is described. This work involved use of 181 artificially infested calves. The drug was formulated at a concentration of 10% m/v levamisole base in a solvent system promoting dermal absorption and was applied to both sides of the spine in the lumber region at a dose rate of 10 mg levamisole base per kg livemass. A consistent performance was achieved in these investigations, the results from all of which were based upon necropsy findings. Efficacy of treatment was assessed against the third and fourth larval stages and fifth stage larvae/adult worms of six nematode species; the respective efficacies obtained were Haemonchus placei 72,0%; 99,3%; and 100%: Ostertagia ostertagi 85,5%; 38,1% and 74,5%: Cooperia spp. 98,9%; 99,9% and 100%: Bunostomum phlebotomum 83,0%; 100% and 98,5%: Oesophagostomum radiatum 47,4%; 94,9% and 99,6% and Dictyocaulus viviparus 79,5%; 94,1%; 90.9% (fifth stage larvae) and 93,8% (adult worms). The anthelmintic efficacy of levamisole in these experiments is of the same order as that achieved by orthodox methods of administration at dose rates between 7,5 and 10,0 mg levamisole HC1 per kg livemass. These findings add a new dimension to the use of levamisole and to anthelmintic therapy in general.
T-cell and B-cell identification in the diagnosis of lymphoproliferative disease. A review.
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