PubMed Health⌕ Search

Biomedical subjects

B R Jennings

Publications and source records attributed to B R Jennings.

At least 19 recordsLinked to original sources
PubMed1989

Beta 2-microglobulin levels in patients with renal insufficiency.

beta 2-microglobulin (beta 2M) has been implicated in the pathogenesis of amyloidosis in long-term dialysis patients. beta 2M levels were measured in patients with chronic renal failure: before and after conventional hemodialysis in 30, before and after high-flux (HF) hemodialysis in 35, and during the first hemodialysis treatment in five patients, as well as in the serum and peritoneal fluid of 13 patients who were receiving continuous ambulatory peritoneal dialysis (CAPD) and in the serum and urine of three patients who had received kidney transplants. Dialysis patients had markedly elevated beta 2M levels; prehemodialysis values were not significantly different for patients receiving conventional v HF hemodialysis. Most of these patients were functionally anephric, and the beta 2M levels did not correlate with age, sex, or time on dialysis. In patients receiving conventional hemodialysis using cellulose acetate membrane, beta 2M levels increased 25.4% after hemodialysis, whereas in patients receiving HF hemodialysis using polysulfone membrane, beta 2M levels decreased significantly (43.0%) after hemodialysis. End-stage renal disease patients dialyzed for the first time had beta 2M values significantly lower than the other two groups because of residual glomerular filtration rate (GFR). CAPD patients also had lower values because they had an estimated loss of 80.4 mg/d of beta 2M in the dialysate fluid. In patients with chronic renal failure, beta 2M levels paralleled the increase in serum creatinine. Patients who received kidney transplants had a dramatic decrease in beta 2M levels that correlated with improvement in GFR. beta 2M correlated with the residual GFR, and its removal was membrane-dependent.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Absence of myelin basic protein in granular cell tumors.

Thirty-one granular cell tumors were studied for the presence of myelin basic protein (MBP) using a monoclonal antibody with a characterized specificity and an immunoperoxidase technique. The tumors studied were from all areas of the body, from both sexes, and from nine decades of age. All the tumors stained negatively for MBP. One brief report using a monoclonal antibody had noted positive staining for MBP in granular cell tumors. A more recent study using polyclonal antibodies found negative staining for MBP in Schwann cell neoplasms including granular cell tumors. This study, using an immunohistochemical technique, demonstrated the absence of an MBP marker in granular cell tumors of diverse location despite the fact that granular cell tumors are widely held to be of Schwann cell origin.

Antibodies, Monoclonal↗
PubMed1987

Serology of Naegleria fowleri and Naegleria lovaniensis in a hospital survey.

An avidin-biotin horseradish peroxidase method was used to detect antibodies to Naegleria fowleri and N. lovaniensis in human serum samples. Antibodies were detected in 101 specimens from 115 hospital patients ranging in age from 15 to 98 years. Class-specific anti-immunoglobulins identified antibodies as IgG and IgM. IgG antibody titers to both species ranged from 1:20 to 1:640. Seven of 15 serum samples collected from newborn infants also demonstrated IgG antibodies to these organisms with a titer range of 1:20 to 1:80. The immunoperoxidase test and Western blot analysis of selected serum samples demonstrated a close similarity in serological results between N. fowleri and N. lovaniensis.

Adolescent↗
PubMed1986

Electrofluorescence study of polycyclic hydrocarbon diol-epoxide binding to DNA.

By the use of a novel electrofluorescence method, estimates have been made of the geometry of binding to DNA of racemic mixtures of the anti-diol-epoxide derivatives of three polycyclic hydrocarbon carcinogens. These anti-configurations bind in a manner consistent with the planar diol-epoxide ring's being inclined at approximately 50 degrees to the DNA axis. This is true for the derivatives of benzo(a)pyrene, benz(a)anthracene and 3-methylcholanthrene. This binding is thus different from the regular intercalative interaction associated with the native hydrocarbons. As the (+ anti)-diol-epoxides are thought to be the initiatory compounds for carcinogenesis, the common binding characteristics for the three hydrocarbons may be significant in understanding the molecular interactions precursive to cancer.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1986

Selective screening of hospitalized patients for the presence of asymptomatic hepatitis B virus carriage: predictability based on census tract data.

Review of all hepatitis B surface antigen-positive patients reported to the county health department over the past 3 years showed that 60% of patients had been diagnosed at our hospital, which serves an inner city, predominantly black, indigent population. Sera from 524 adult patients admitted to the hospital were prospectively collected and tested for hepatitis B surface antigen, eight (1.5%) of which were antigen-positive. Census tract data allowed us to perform selective screening of sera from 95 other patients who were subsequently hospitalized and deemed "high risk" for hepatitis B infection. Nine of 95 (9.5%) selectively screened samples were positive for hepatitis B surface antigen, which represented a significantly higher rate of antigen carriage (P less than 0.0001) in hospitalized patients from "high risk" areas than that found in the general population screen. The methodology presented herein may be useful in providing a means of identifying hepatitis B surface antigen-positive patients from adult, urban, indigent care populations.

Adult↗
PubMed1985

Effect of additives on liposomes: an electric birefringence study.

Under the influence of an electric field, vesicles in suspension partially deform or orientate, rendering the medium optically birefringent. The amplitudes of the birefringence under fields of variable amplitude lead to evaluation of the anisotropy of the electrical delta alpha and optical delta G polarisabilities of the vesicles. By using pulsed fields, rates of establishment and decay of birefringence enable vesicle sizes d to be measured. Samples of 9:1 phosphatidylcholine-phosphatidylserine liposome suspension in water were studied in the presence of various additives, including sucrose, an antibiotic (streptomycin), a steroid (dexamethasone), an anaesthetic (lignocaine) and a fluidising agent (benzyl alcohol). The changes in the three parameters delta alpha, delta G and d were different for each additive and are thought to be indicative of the mode of interaction of each. Electric birefringence also appears to be a rapid means of detecting structure changes.

Benzyl Alcohol↗
PubMed1978

Characterization of proteoglycan and the proteoglycan--hyaluronic acid complex by electric birefringence.

An electric field causes partial alignment of macromolecules in a dilute solution. The accompanying changes in the solution birefringence offer a sensitive and quick means of monitoring the rates of particle orientation and hence the size of the solute molecules. Such measurements are reported for dilute solutions of proteoglycans in the absence and presence of added hyaluronic acid. The proteoglycan molecules are shown to be some 580 nm long. In the presence of hyaluronic acid they form aggregates that appear to be consistent with the model previously proposed in which the proteoglycans attach radially to the extended hyaluronic acid chain. The electric-birefringence relaxation rates indicate aggregates of similar length to that of the extended hyaluronic acid chain, with the proteoglycans spaced on average at 29nm intervals. A proteoglycan sample the cystine residues of which had been reduced and alkylated showed no evidence of aggregation with hyaluronic acid up to the concentrations of the acid corresponding to 1% of the total uronic acid content. The electric-birefringence method is shown to have a large potential in the study of associating polysaccharide solutions.

Alkylation↗
PubMed1977

The effect of antibiotics on the electrical polarisability of aqueous suspensions of bacteria.

The orientation of washed Escherichia coli bacteria in suspension induced by applied a.c. electric fields has been monitored by observing the accompanying changes in the intensity of light scattered by the suspension. The data enable the anisotropy of electrical polarisability deltaalpha to be determined. Changes in deltaalpha due to the addition of various antibiotics to the suspension have been measured as a function of both the antibiotic concentration and the temperature of the suspension. The results are taken to indicate that there is an accumulation of the antibiotic molecules at the bacterial surface.

Adsorption↗
PubMed1977

T-lymphocytes and survival of head and neck squamous cell carcinoma.

The thymus-dependent lymphocytes (T cells) were enumerated in the peripheral circulation of 38 patients with histologically demonstrated squamous cell carcinoma of the head and neck. We have previously shown that this "total" T-cell count correlates well with degree of tumor involvement. A lower percentage of T cells were shown in patients with more advanced malignant neoplasms. Here we present follow-up data on these patients to evaluate the efficiency of the T-cell test in determining survival prognoses. We found no evidence that results of this test can extend prognostic abilities above those based on clinical staging. The survival data from six patients treated with a chemoimmunotherapy regimen of BCG vaccine, methotrexate sodium, and isoniazid did not demonstrate an increased survival time compared to patients at similar clinical stages who were treated by conventional use of surgery and irradiation.

Adult↗
PubMed1976

T-cell rosette test in squamous cell carcinoma of the head and neck.

The percentage of total T-lymphocytes was measured in 38 patients with histologically diagnosed squamous cell carcinoma of the head and neck. This measure of cellular immunity, which appears to be important in tumor-cell destruction, is demonstrably lowered in advanced stages of this disease. With the use of this test, the effect of a combined chemoimmunotherapeutic regimen consisting of methotrexate sodium, isoniazid, and BCG vaccine was sutdied. In this small series, no decrease of the T-cell count following treatment by methotrexate was demonstrated, except when a high dosage followed by leucovorin calcium was used. The BCG vaccine appeared to enhance T-cell counts, and one patient who was treated with cryosurgery had a dramatic increase in circulating T-lymphocytes. The T-cell test may be of clinical importance in the development of treatment sequences that provide maximum reduction of tumor cell mass while preserving host T cells.

Adult↗
PubMed1976

An electro-optic study of the effect of certain aminoglycoside antibiotics on the electrical polarizability of sensitive, dependent and resistant strains of Escherichia coli.

A study has been made of the effect of certain aminoglycoside antibiotics on the electrical properties of the surfaces of one sensitive, two resistant and one dependent form of E. coli K-12. The method employed was to observe the change in scattered light produced when the bacteria in suspension are orientated by an applied a. c. electric field. The effect of the antibiotics has been analysed in terms of drug accumulation at the bacterial surface. Differences have been noted in the responses of the sensitive form to different aminoglycosides and an attempt has been made to correlate these differences with mimimum inhibitory concentrations. Differences have also been noted in the response of certain resistant and dependent forms of E. coli to streptomycin.

Anti-Bacterial Agents↗
PubMed1975

The effect of neomycin and streptomycin on the electrical polarisability of aqueous suspensions of Escherichia coli.

Aqueous suspensions of bacteria scatter light strongly. In addition, the bacteria exhibit strong induced dipole moments in an electric field. In this note we report how, by measuring the intensity of the scattered light, the electric polarisability (alpha) of Escherichia coli could be monitored as small quantities of antibiotics were added to the suspensions. The effect of the presence of quite small quantities of antibiotic on the electrical polarisability, which gave rise to the induced dipole, was dramatic. From the hypothesis that alpha had its origins in the bacteria-solvent interface, a theory is presented which adequately accounts for both alpha and its changes in the presence of these antibiotics. The study is taken to suggest that the antibiotic molecules were adsorbed on to the bacterial surface thereby reducing the surface charge. This in turn reduces the number of counterions and the apparent induced dipole moment. Because the electric-field scattering method is both quick and sensitive to changes in alpha, it may prove a valuable method for the study of antibiotic action on cell and microorganism surfaces.

Escherichia coli↗