Search PubMed⌕ Search

Biomedical subjects

D R Bell

Publications and source records attributed to D R Bell.

At least 127 records · Page 7Linked to original sources
PubMed1982

Persisting nutritional neuropathy amongst former war prisoners.

Of 898 former Far East prisoners of war, assessed between 1968 and 1981, 49 (5.5%) had evidence of persisting symptomatic neurological disease dating back to their periods of malnutrition in captivity. The commonest syndromes were peripheral neuropathy (often of "burning foot" type), optic atrophy, and sensori-neural deafness. Though nutritional neuropathies disappeared soon after release in most ex-Far East prisoners of war, in some they have persisted up to 36 years since exposure to the nutritional insult.

Amblyopia↗
PubMed1982

Effects of increased venous pressure on albumin- and IgG-excluded volumes in skin.

The effect of increased venous pressure on the exclusion of plasma albumin and gamma-immunoglobulin G (IgG) in skin interstitium was studied in anesthetized rabbits. In eight rabbits, venous pressure in the left leg was increased from 7 to 26 mmHg, while the right leg served as a control. Samples of plasma and prenodal popliteal lymph were collected for 4 h before taking samples of heel skin. The extracellular and plasma spaces in the tissue samples were measured using 51Cr-labeled ethylenediaminetetraacetic acid (EDTA) and 125I-labeled human serum albumin, respectively. The protein spaces were calculated from measurements of endogenous albumin and IgG concentrations using rocket electroimmunoassay. For control skin, albumin and IgG were both excluded from 50% of the interstitial space. The interstitial space after venous congestion was increased 1.4 times control. There was a washout of interstitial albumin and no change in the albumin-excluded volume fraction. For IgG, there was no change in the extravascular mass and a decrease in the excluded volume fraction. Changes in the interstitial gel matrix of skin were different from those in visceral organs and consistent with a greater amount of collagen.

Animals↗
PubMed1982

Effects of increased venous pressure on albumin- and IgG-excluded volumes in muscle.

The effect of elevated venous pressure on the extravascular distribution space of albumin and gamma-immunoglobulin G (IgG) in muscle was studied in anesthetized rabbits. In nine rabbits, venous pressure in one leg was increased from 8 to 28 mmHg while the other leg served as a control. Samples of plasma and prenodal muscle lymph were collected for 4 h before taking samples of the gastrocnemius muscle. Lymph was collected from a femoral lymphatic after ligating the popliteal efferent lymphatic. The extracellular and plasma spaces in the tissue samples were measured using 51Cr-labeled ethylenediaminetetraacetic acid (EDTA) and 125I-human serum albumin, respectively. The protein spaces were calculated from measurements of endogenous albumin and IgG concentrations using rocket electroimmunoassay. Albumin and IgG were both excluded from 50% of the interstitial space at lymph concentration. After venous congestion, the interstitial volume was twice that of control. Lymph flow increased from 0.82 +/- 0.18 to 4.44 +/- 0.64 microliters/min. The extravascular mass of albumin and IgG increased. There was no change in the excluded volume fraction for albumin but a decrease in that for IgG. Changes in interstitial protein exclusion in skeletal muscle after pressure elevation may not be important in oncotic buffering of the edema.

Animals↗
PubMed1982

Thoracic duct lymph flow after pancreatitis: role in circulatory collapse.

We examined the effects of acute hemorrhagic pancreatitis on thoracic duct lymph flow and its protein concentration. Thoracic duct lymph flow increased and the protein concentration decreased. These changes in the lymph were associated with steady decreases in arterial pressure and cardiac output and increase in systemic vascular resistance. The results suggest that the increased lymph flow and decreased protein concentration were due to either an ultrafiltration causing a dilution of the lymph protein concentration or to the heterogeneous origin of thoracic duct lymph such that redistribution of blood flow to the essential beds (eg, kidneys) after arterial hypotension altered the lymph flow and its protein concentration. The increase in filtration and the absence of a compensatory "autotransfusion" during arterial hypotension may be a mechanism contributing to circulatory shock in acute pancreatitis.

Acute Disease↗
PubMed1981

Methyl-CCNU, 6-thioguanine, and 5-fluorouracil in advanced colorectal cancer.

Consecutive studies were undertaken in advanced colorectal adenocarcinoma, comparing two different schedules of the combination methyl-CCNU, 6-thioguanine, and 5-fluorouracil in 89 patients. The two schedules exhibited similar efficacies, with a combined complete and partial remission rate of 17%, a median response duration of 36+ weeks, and a median survival of 53+ weeks. Significant symptomatic benefit was seen in 52% of patients. Toxicity was predominantly hemopoietic and gastrointestinal, being acceptable overall, with only minor qualitative differences between the two protocols. These triple-drug regimens exhibit response rates and survival patterns comparable with those reported for other multidrug combinations and some single agents. It would appear that major improvements in the management of advanced-stage disease must await the availability of more efficacious agents used alone or in combination.

Adenocarcinoma↗
PubMed1981

Meningeal carcinomatosis in small cell carcinoma of the lung.

Cerebral and meningeal metastases are increasingly important complications in small cell anaplastic carcinoma of the lung. In a study at this institution, 60 evaluable patients received intensive chemotherapy without prophylactic cranial irradiation or other prophylactic measures. The complete plus partial remission rate was 78 percent with a median survival of 49+ weeks (range eight to 106+ weeks) for those with a complete response and 18+ weeks (range six to 67 weeks) for those with a partial response, all of which are comparable to other reported series. In 11 patients (18 percent) meningeal carcinomatosis has developed. Forty-two percent of the patients with a relapse have exhibited meningeal carcinomatosis and in 27 percent of the patients with a relapse it was the only site of relapse. Cerebral metastases occurred in 27 percent of those who had a relapse, and in 12 percent this was the sole site of relapse. Simultaneous meningeal carcinomatosis and cerebral metastases occurred in 8 percent of the patients with a relapse. The median time to meningeal relapse was 27 weeks (range 12 to 60 weeks) compared with 25+ weeks (six to 106+ weeks) over-all, and the median survival was 28 weeks (range 14 to 82 weeks) compared with 25+ weeks (two to 106+ weeks) for the whole group with small cell carcinoma of the lung. Meningeal involvement in small cell carcinoma of the lung must now be considered a sanctuary site of equal importance to cerebral metastases. To prevent and treat this complication will necessitate evaluation of all available modalities, including cranial and spinal irradiation, intrathecal chemotherapy and systemic agents that readily cross the blood-brain barrier.

Adult↗
PubMed1981

Microembolization induced oxygen utilization impairment in the canine gracilis muscle.

Impaired peripheral oxygen utilization coinciding with an elevated cardiac index, venous oxygen tension, and serum lactate with the loss of reactive hyperemic response have been observed in a large series of resuscitated trauma patients. We tested the hypothesis that these clinical findings were due to an alteration of the microcirculation caused by embolization of intravascular particulate matter. To test this hypothesis, we used the bilateral pump-perfused, isolated canine gracilis muscle preparation which we subjected to microembolization with 15 micrometers polystyrene spheres. Prior to microembolization, oxygen consumption was flow-limited up to 6 ml min-1 (r = .928) and at higher flows, oxygen consumption was independent of flow. Following microembolization, the relationship of oxygen consumption and blood flow remained correlated (r = .893), but there was less oxygen consumption at any given flow rate (P less than .05). Imidazole, 30 mg kg-1, IP administered to prevent platelet aggregation, resulted in the return of oxygen utilization to the preembolization value. PVO2 of the microembolized muscle was significantly higher than in the contralateral muscle, which was abolished after imidazole administration. These data suggest that microembolization leads to an oxygen utilization defect similar to that observed in the resuscitated trauma patient. Since this defect was reversed by imidazole administration, a humoral mechanism in the microcirculatory bed may act to restrict oxygen utilization following microembolization and trauma.

Animals↗
PubMed1980

Early kinetics of large molecule transport between plasma and lymph in dogs.

Using a mathematical model in which the interstitial space resembled a gel filtration column, Watson and Grodins (Microvasc. Res. 16: 19-41, 1978) predicted that molecules larger than serum albumin should have an early approach to steady state in lymph faster than that of serum albumin. This hypothesis was tested in dogs anesthetized with pentobarbital sodium by use of radiolabeled albumin and fibrinogen and a fluorescent dextran and by collecting lymph from cannulas in the prepopliteal lymphatics of the hind paws. The steady-state lymph-plasma concentration ratios (R), measured chemically, were 0.24 +/- 0.02 (SE, n = 16) for albumin and 0.040 +/- 0.004 (n = 16) for fibrinogen. In 5 h, albumin and fibrinogen tracers had reached approximatly 25 and 50% of their steady-state levels, respectively. The dextran (mol wt 1.5 x 10(5)) behaved like fibrinogen. The data support the hypothesis that the interstitium has nonrestricting pathways, and that there are gel regions that have a low permeability to very large molecules.

Animals↗
PubMed1980

Exclusion of plasma proteins in interstitium of tissues from the dog hind paw.

Exclusion of plasma albumin and fibrinogen from portions of the extravascular sucrose space in tissues of the hind paw of anesthetized dogs was studied by use of radioactive traces. Thirty hours after a bolus injection of the labeled proteins, tracer concentrations were measured in plasma, prenodal popliteal lymph, and samples of hind paw skin, tendon, muscle, and toe pad. In a few experiments, constant plasma levels of tracer sucrose were maintained for 2 h before terminal sampling. In all experiments a vascular volume marker was given 15 min before termination. A linear correlation was found between the amounts of extravascular protein tracers in the tissue samples and their concentrations in lymph from the same paw, as would be expected if their actual interstitial concentrations were closely related to their lymph concentrations. For albumin, the extravascular distribution volume calculated at lymph concentration was less than the sucrose space for all tissues except toe pad. For fibrinogen, the extravascular distribution volume was less than albumin and sucrose for all tissues except skin. Differences in pattern and degree of exclusion may reflect the differences in interstitial gel-phase composition and structure.

Animals↗
PubMed1980

The chemotherapy of onchocerciasis V. A standard method for the determination of microfilarial density in skin snips.

The microfilarial density in 400 skin snips from 100 patients was determined using the standard technique of the Onchocerciasis Chemotherapeutic Research Centre (OCRC method), the method used by the Onchocerciasis Control Programme (OCP method), and also after collagenase digestion. The OCRC method was fairly consistent and detected 84% of the total microfilariae. The OCP method gave a density which was consistently 20% less than the OCRC method, indicating that the increase in weight in skin snips following incubation in saline was fairly predictable. It is concluded that collagenase digestion is not worthwhile as a routine technique in chemotherapeutic trials, for which the OCRC method is recommended.

Humans↗
PubMed1979

Strongyloides stercoralis infection in former Far East prisoners of war.

Out of 602 consecutive people who had been prisoners of war in the Far East and were screened for tropical diseases, 88 (15%) were found to have Strongyloides stercoralis infection a mean period of 30 years after their return from the tropics. The classical strongyloid creeping eruption was the most common symptom (84%), while gastrointestinal disturbances were rare (5%). Thiabendazole was highly effective in eradicating the infection. Strongyloidiasis is an important condition, as when the host is immunosuppressed fatal hyperinfection may occur. Many undiagnosed cases of strongyloidiasis must exist among former prisoners of war, and it is thus important to identify and treat these patients.

Aged↗
PubMed1979

Schistosoma mansoni: activity responses in vitro to praziquantel.

The effects of praziquantel, a novel antischistosomal compound, on the activity of adult Schistosoma mansoni (Liverpool strain) in vitro were investigated. Worm activity was modified at all concentrations of praziquantel. High concentrations (above 0.5 microgram/ml) produced rapid paralysis, whilst low concentrations of praziquantel stimulated worm activity. It is concluded that such activity modification could lead to worm displacement in vivo.

Animals↗