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Biomedical subjects

B Bennett

Publications and source records attributed to B Bennett.

At least 55 records · Page 3Linked to original sources
PubMed1986

Haemoglobin concentration and linear cardiac output, peripheral resistance, and oxygen transport.

Increasing the haemoglobin concentration results in increased oxygen transport at the cost of increased blood viscosity. This suggested the concept of an optimum packed cell volume for maximising oxygen transport and a study was therefore conducted seeking supportive evidence. Linear cardiac output was measured as minute distance by Doppler ultrasound in 40 patients with haemopoietic disorders who had stable haemoglobin concentrations ranging from 30 to 200 g/l. The correlation between haemoglobin concentration and minute distance (r = -0.45; p less than 0.01) was negative, and correlations between haemoglobin concentration and mean blood pressure (r = 0.66; p less than 0.001) and haemoglobin concentration and peripheral resistance (r = 0.64; p less than 0.001) were positive. Calculated oxygen transport increased across the whole range of haemoglobin values. These results suggest that adjustment of peripheral resistance in response to oxygen availability overrides the influence of blood viscosity on cardiac output and that the optimum packed cell volume for oxygen transport is the highest that can be achieved.

Biological Transport↗
PubMed1986

Human monorchism: a clinicopathological study of unilateral absent testes in 65 boys.

We reviewed the medical records of 65 boys with surgically and pathologically proved monorchism. A striking laterality to the left side was identified. In 83 per cent of the patients wolffian structures were present and in 20 per cent microscopic evidence of a terminal nubbin of hyalinized, calcified or hemosiderin-containing tissue was noted. These findings strongly suggest that in most instances of monorchism a testis had been present and had undergone subsequent in utero degeneration. Characterization of the hormonal changes associated with unilateral absent testes was done by determining fasting morning levels of luteinizing hormone and follicle-stimulating hormone. In a subgroup of monorchid boys and age-matched prepubertal unilateral cryptorchid boys luteinizing hormone release factor stimulation also was performed to determine if endocrine analysis could predict the absence of 1 testis.

Adolescent↗
PubMed1986

The adjuvant activity of nonionic block polymer surfactants. III. Characterization of selected biologically active surfaces.

We evaluated the molecular and physicochemical properties of surfaces formed by defined layers of block copolymers which were especially effective as adjuvants or in the induction of granulomas. The copolymers which were adjuvants formed hydrophilic surfaces with a large area. They bound protein in a way which left it particularly accessible to antibody and induced the activation of complement. Copolymers which induced granulomas, in contrast, formed hydrophobic crystalline surfaces. They bound less protein and did not activate complement, but were toxic for macrophages. Their surfaces were found to be similar to those of the mycobacterial glycolipid trehalose-6,6'-dimycolate or quartz, in that they consisted of regular geometric arrays of hydrophilic and hydrophobic adsorptive domains. These studies demonstrated that changes in the size and arrangement of hydrophilic and hydrophobic blocks in copolymers produce a diversity of surface physicochemical properties which correlate with biologic activity.

Adjuvants, Immunologic↗
PubMed1986

Mechanisms of injury in unilateral testis torsion.

We investigated the mechanisms of injury involved in unilateral testis torsion as well as the interventional effects of orchiectomy at 48 h and immunosuppression with corticosteroids in rats. Torsion was associated with abnormal contralateral testis histology and raised antilymphocytes and antisperm antibody titers. Both orchiectomy and steroid administration lessened these findings, suggesting that an immunological process underlies the abnormality seen in this experiment model.

Animals↗
PubMed1986

Homicide and depression.

The relationship of depression to homicide has been overlooked in clinical psychiatry. The authors report on six homicidal depressed control compare them with nonhomicidal depressed control subjects. They also analyze data from 81 case summaries found elsewhere in the literature. Their preliminary data suggest that homicidal depressed patients are more likely to have a personality disorder, to have been physically abused as a child, to abuse alcohol or drugs, and to be suicidal than are nonhomicidal depressed patients. In homicidal patients, the event precipitating the depression is more likely to be sexual infidelity, either real or fantasized.

Adult↗
PubMed1985

The plasma inhibitors of plasminogen activator, studied by a zymographic technique.

A zymographic technique for the detection of inhibitors of plasminogen activators has been applied to the analysis of plasma. Two inhibitors have been demonstrated; one inhibited plasmin with consequent apparent inhibition of urokinase and tissue-type plasminogen activator activity; it was identified as alpha 2-antiplasmin. The second inhibitor, as yet unidentified, had a molecular weight of about 40K. It inhibited urokinase and tissue-type plasminogen activator but had no effect on plasmin.

Blood↗
PubMed1985

Direct measurement of antibody production in cell suspensions using an enzyme-linked immunosorbent assay.

We have developed an enzyme-linked immunosorbent assay (ELISA) to measure antibody production in cell suspensions using highly sensitive avidin-biotinylated peroxidase (ABC) reagents. The cells are serially diluted in media and placed directly on a standard antigen-coated microtiter plate for 6 h, and the plate is then washed and processed to determine the bound antibody. The amount of antibody detected is reduced by puromycin indicating in vitro synthesis. Standard errors of the means of optical density readings of replicate samples are less than 10%. The background readings and readings obtained using non-immune cells are negligible, demonstrating no significant contamination by endogenous peroxidases.

Animals↗
PubMed1985

Prostatic calculi: a review.

Prostatic calculi are rare in children, infrequent below age 40, and common in males over 50. They may be solitary but usually occur in clusters and are associated with some other disease process (nodular hyperplasia, prostatic carcinoma, metabolic abnormalities). They are most often asymptomatic; however, symptoms that may be attributable to prostatic calculi include reduction of the urinary stream, prostatism, and intense lower back and leg pain. Treatment may be accomplished by transurethral resection, but prostatectomy is the best means to insure complete removal. Prostatic calculi may form by two related mechanisms with obstruction and stasis of prostatic fluid as central entities in both. These mechanisms are calcification of corpora amylacea and simple precipitation of prostatic secretion. They may arise spontaneously, initiating an inflammatory reaction that contributes to their growth, or they may arise as the consequence of another pathologic situation producing acinar obstruction. It appears that infection probably occurs secondary to stone formation.

Adult↗
PubMed1985

Fertility in young men and women after treatment for lymphoma: a study of a population.

All young patients in the Grampian area attending the lymphoma review clinic who had received first line treatment for Hodgkin's disease and had attained complete remission without subsequent relapse were studied between 1980 and 1983. Chemotherapy with MVPP (mustine, vinblastine, procarbazine, and prednisolone) had more severe effects on the fertility of men than that of women; younger women and those taking oral contraceptives were more likely to retain fertility than those over 30 or not taking the pill at the time of chemotherapy, but these two effects could not be differentiated. Premature menopause was common after treatment with MVPP. Mantle radiotherapy had no discernible effect on gonadal function.

Adolescent↗
PubMed1985

Platelet release protein which inhibits plasminogen activators.

An inhibitor of plasminogen activator has been identified in human platelets by the technique of sodium dodecyl sulphate polyacrylamide gel electrophoresis and zymography. The inhibitor has a molecular weight of about 40 000 and is distinct from known plasma protease inhibitors. It is associated almost exclusively with platelets, with only trace amounts in platelet free plasma. The inhibitor is released during platelet aggregation or in vitro coagulation. This inhibitor inhibits both tissue type plasminogen activator and urokinase but has no effect on plasmin. It forms a 1:1 complex with tissue type plasminogen activator, which retains activity detectable under the analytical conditions used. A similar complex with urokinase either forms less readily or retains less activity.

Blood Platelets↗
PubMed1985

Exposure to vinyl chloride and angiosarcoma of the liver: a report of the register of cases.

The Association of Plastic Manufacturers in Europe maintains a register of all cases of angiosarcoma of the liver (ASL) resulting from exposure to vinyl chloride monomer (VCM). This register has recorded all known VCM related cases of the disease worldwide that have been histologically confirmed. Although likely to be incomplete, it is the most comprehensive tabulation of such cases available and, by the end of 1984, 118 men had been registered. The information from analysis of the cases currently on the register is used to make an approximate projection of the number of cases to be expected in the future. The conclusion from this projection is that the industry is reaching the halfway stage in the appearance of VCM related ASL.

Adult↗
PubMed1985

The effect of captopril on urinary protein excretion in puromycin aminonucleoside nephrosis in rats.

We investigated the effect of captopril, an orally active angiotensin converting enzyme inhibitor, on urinary protein excretion in puromycin aminonucleoside nephrotic rats. The administration of captopril (10 mg/100 g body weight) decreased proteinuria on days 10-14 following the administration of puromycin aminonucleoside (73.0 versus 125.0 mg, p less than 0.01), without affecting glomerular filtration rate. The beneficial effect of captopril was not abolished by the continuous intravenous infusion of angiotensin II (10 micrograms/kg/h for 9 days) or subcutaneous injections of aprotinin (50,000 KIU/day for 3 days). Indomethacin, in moderate (5 mg/kg/day for 3 days) or high (10 mg/kg/day) doses, abolished the captopril attenuation in urinary protein excretion. The salutory effect of captopril was characterized by a reduction in the fractional excretion of protein without compromising the glomerular filtration rate. No difference in renal ultrastructure was noted in captopril-treated versus control animals. Captopril was ineffective in reducing urinary protein excretion in rats with adriamycin-induced glomerulopathy. We conclude that captopril acts to reduce proteinuria in renal disease states arising from depletion of the glomerular basement membrane polyanion. The mechanism of action is postulated to be an alteration in renal hemodynamics, namely increased blood flow and a decrease in the ultrafiltration coefficient, that are the consequence of increased intrarenal prostaglandin production.

Angiotensins↗
PubMed1984

Transferrin in disease. I: A potential prognostic indicator in patients undergoing bone marrow transplantation.

Transferrin levels were measured immunochemically and the levels of several other plasma proteins were estimated by high resolution agarose gel electrophoresis in serial serum samples from nine patients undergoing bone marrow transplantation for aplastic anemia or leukemia. Three of five patients with low pretreatment transferrin levels died during initial hospitalization, and the other two suffered severe complications prior to recovery. All four patients with pretreatment transferrin levels within the normal range were discharged, three of them with minimal complications. Serial studies demonstrated that transferrin levels fell with the onset of infections or graft-versus-host disease and rose with recovery. Similar changes were not seen with any of the other plasma proteins measured. These results suggest that measurement of serum transferrin may reveal important prognostic information about patients undergoing bone marrow transplantation.

Adolescent↗
PubMed1984

Transferrin in disease II: defects in the regulation of transferrin saturation with iron contribute to susceptibility to infection.

Patients with leukemia were found to have a high percentage of saturation of their serum transferrin with iron to an extent only rarely observed with other malignancies. This was associated with a reduced ability of their serum to inhibit the growth of a test strain of Pseudomonas aeruginosa. Serum iron, transferrin, and related parameters were measured serially in patients undergoing bone marrow transplantation for leukemia or aplastic anemia. It was found that a high proportion of these patients also have a high saturation of their transferrin with iron. This was related to three distinct physiologic deficits: a low level of serum transferrin; a high level of iron; and an inability to reduce the level of serum iron during infection. Three of six patients who were unable to reduce their serum during fever and infection subsequently died of sepsis. These data support the hypothesis that derangements in nonspecific serologic defense mechanisms involving iron contribute to susceptibility to infection in patients with leukemia undergoing bone marrow transplantation.

Adolescent↗