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Biomedical subjects

D A Russell

Publications and source records attributed to D A Russell.

At least 73 records · Page 4Linked to original sources
PubMed1985

Anaphylactic-like reaction of small intestinal epithelium in parasitized guinea-pigs.

Antigens derived from Trichinella spiralis were used to challenge, in vitro, sensitized jejunum from infected guinea-pigs while monitoring ion transport properties of the tissue. Antigen challenge resulted in dose-dependent increases in trans-epithelial electrical potential difference and short circuit current. Both antigen-stimulated electrical alterations and Schultz-Dale contractions were demonstrated in small intestinal tissue after the passive transfer of immune serum containing anti-trichinella homocytotropic antibodies.

Anaphylaxis↗
PubMed1983

Exponential evolution: implications for intelligent extraterrestrial life.

Some measures of biologic complexity, including maximal levels of brain development, are exponential functions of time through intervals of 10(6) to 10(9) yrs. Biological interactions apparently stimulate evolution but physical conditions determine the time required to achieve a given level of complexity. Trends in brain evolution suggest that other organisms could attain human levels within approximately 10(7) yrs. The number (N) and longevity (L) terms in appropriate modifications of the Drake Equation, together with trends in the evolution of biological complexity on Earth, could provide rough estimates of the prevalence of life forms at specified levels of complexity within the Galaxy. If life occurs throughout the cosmos, exponential evolutionary processes imply that higher intelligence will soon (10(9) yrs) become more prevalent than it now is. Changes in the physical universe become less rapid as time increases from the Big Bang. Changes in biological complexity may be most rapid at such later times. This lends a unique and symmetrical importance to early and late universal times.

Animals↗
PubMed1979

Physiological characterization of a biphasic immune response to Trichinella spiralis in the rat.

Secondary infection with Trichinella spiralis in the rat was associated with a host response that prevented approximately 80% of the total number of larvae recovered after primary infection from embedding in the intestine. The host response occurred within 15 min after contract of the parasite with intestinal mucosa and was not associated with acute inflammatory cell infiltrates or with the pathophysiology of the primary infection. Eventual rejection of the residual population of embedded worms occurred between four and eight days after infection and involved tissue changes similar to those attending worm rejection during primary infection. Elimination of enteric stages of T. spiralis in primary infection probably involves a single response aimed at the expulsion of established worms. In contrast, immune rejection of worms in secondary infection involves physiologically and presumably immunologically distinct "early" and "late" responses, with each response having a different developmental stage of the parasite as its target.

Animals↗
PubMed1979

Acedapsone in the prevention of leprosy: field trial in three high prevalence villages in Micronesia.

The 1,659 non-leprous people in a Micronesian population experiencing an annual leprosy incidence rate of about 7/1,000 were offered 15 acedapsone (DADDS) injections during 1967--1970 for leprosy prevention purposes. Subsequent annual surveillance showed an initial cessation of new cases during the 3-year DADDS campaign, followed by a resumption of cases thereafter at a yearly level of about 2/1,000 with a longer pause and slower rise among those who received the full regimen. A secondary wave of cases that has occurred since 1973 among children born after 1968 shows that post-campaign transmission occurred, probably principally from relapsing multibacillary cases with onset before the campaign. Recommendations are made for a balanced, long-term control program with DADDS preventive treatment limited to contacts of multibacillary cases.

Acedapsone↗
PubMed1977

Acedapsone treatment of leprosy patients: response versus drug disposition.

In 22 lepromatous Filipino patients receiving their first injection of 225 mg acedapsone (DADDS), dapsone (DDS), and monoacetyl DDS (MADDS) were present in plasma in approximately equal quantities. Peak levels of parent drug, DDS, and MADDS occurred between 22 and 35 days. The half-times of disappearance (T1/2) from plasma were 43 days for DDS and MADDS and 46 days for DADDS. Acetylator phenotyping with sulfamethazine (SMZ) and DDS showed that 17 patients were rapid and 5 patients were slow acetylators. Correlations between acetylation of SMZ and DDS after DDS and of acetylation of DDS after DDS and DADDS were highly significant. However, acetylation of DDS after DADDS did not differentiate the patients into acetylator phenotypes. The T1/2 of DDS after DDS in the patients was directly related to the minimum levels of DDS at 77 days after DADDS treatment. These minimum levels were 8-fold higher than the minimum inhibitory concentration (MIC) of DDS for Mycobacterium leprae in mice and rats, but not all patients responded satisfactorily. No relationship could be demonstrated between the bacteriologic response and any of the pharmacologic parameters examined in these Filipino patients. In a companion study, minimum levels of DADDS, MADDS, and DDS were determined in 447 leprosy patients of all disease types from the Karimui District of Papua New Guinea who had been receiving 225 mg DADDS every 70 to 80 days for the past 5 years. All patients exhibited DDS levels above the MIC of DDS for M. leprae, no significant differences in plasma sulfone levels were found among disease types, no relationship between rate of healing in paucibacillary patients and sulfone levels were found, and type of response in multibacillary patients and sulfone levels were unrelated. No substantial accumulation of the sulfones in the Karimui patients receiving continuous therapy with DADDS for 5 years was indicated from a comparison with the levels in the Filipino patients following a single injection of DADDS.

Acedapsone↗
PubMed1975

Association of amyloidosis with erythema nodosum leprosum reactions and recurrent neutrophil leucocytosis in leprosy.

Rectal biopsy in 190 inpatients at a leprosy hospital in the Highlands of Papua New Guinea disclosed 16 patients with secondary amyloidosis. This represented 20% of the patients who had had polar lepromatous leprosy (L.L.) for more than 2 years. Patients with amyloidosis characteristically had either a history of recurrent attacks of erythema nodosum leprosum (E.NH) reactions or chronic trophic ulcers. Levels of the serum component (protein SAA) antigenically related to the amyloid fibril protein AA were monitored, at varying intervals for three months, in lepromatous patients with E.N.L. reaction. The SAA levels rose during E.N.L. reactions in parallel with the neutrophil count. SAA occurred with greatest frequency among patients with LH, while most non-lepromatous patients with detectable SAA had chronic trophic ulcers. The correlation between raised neutrophil count and elevated SAA concentration, observed in this and other studies, suggests that neutrophils are associated with the production of SAA.

Amyloidosis↗
PubMed1975

Acedapsone (DADDS) treatment of leprosy patients in the Karimui of Papua New Guinea: status at six years.

Acedapsone (DADDS), a repository sulfone given by injection five times a year, has been used since 1967 for the treatment of all leprosy patients in the Karimui, an area of diffic-lt access. More than 460 patients have been treated, 336 beginning in November 1967 and continuing through the latest assessment 6 years later. The injections have been well received and they have been administered very regularly. Clinical observations were begun before 1967, as a base-line of assessments was available for the patients whose disease appeared before that time. The response to DADDS therapy has been satisfactory except in 5 of the 28 multibacillary patients in whose smears solid-staining Mycobacterium leprae have reappeared. M. leprae was isolated in mice from three of these patients; one strain has been proven to be completely susceptible to dapsone (DDS), and the other two very probably are. DDS levels in the plasma of these five patients were normal and well above the minimal inhibitory concentration. The most probable explanation is that a few viable M. leprae survived in the presence of inhibitory concentrations of DDS for the 4 to 6 years during which dead bacilli were disintegrating and disappearing from the tissues. The other 23 multibacillary patients responded satisfactorily. The decrease in the number of M. leprae in the skin smears has been most prompt in patients with low initial bacterial loads and in those with borderline lepromatous diagnoses. A high initial bacterial load and a fully lepromatous diagnosis were associated with a slow initial loss of M. leprae in the 1st year, followed by a more rapid loss the next year. All of the multibacillary patients have now been treated by the addition of a 90-day course of rifampicin.

Acetamides↗