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Biomedical subjects

M M Baker

Publications and source records attributed to M M Baker.

14 recordsLinked to original sources
PubMed2002

Investigation into the toxicological effects of Catha edulis leaves: a short term study in animals.

In this study the short term (3 months) toxicological effects of varying levels of Catha edulis leaves were examined on the plasma concentration of liver enzymes and the histopathology of tissue sections of various organs including the liver, kidneys, spleen and testis. Both the biochemical and histopathological data demonstrated, initial signs of Catha edulis toxicity. Our results show a significant increase in plasma levels of alkaline phosphatase (ALP) and alanine aminotransferase (ALT) with all levels of Catha edulis leaves tested and throughout the treatment period. The increase of ALP was more prominent than that of ALT. The plasma levels of aspartate aminotransferase (AST) were only moderately increased at the higher dose (30%) in the later stages of treatment. In addition, a time-dependent gradual increase in indirect bilirubin with a concomitant decrease in direct bilirubin levels was observed with the 30% Catha edulis with no signs of haemolysis. The histopathology of tissue sections of the liver displayed evidence of congestion of the central liver veins as well as acute hepatocellular degenerative and regenerative activities in the tissue sections obtained from animals treated with both 20% and 30% Catha edulis. Similarly, histopathological examination of the tissue sections of the kidneys showed some lesions, and the degree of the lesion increased as the dose of Catha edulis leaves increased including: the presence of fat droplets particularly seen in the upper cortical tubules; acute cellular swelling; hyaline tubules; and acute tubular nephrosis. In contrast, Catha edulis treatment did not affect the spleen and increased the rate of spermatogenesis in male rabbits with the spermatozoa being quite evident, the Leydig cells were in good condition and were not affected by the doses given.

Alanine Transaminase↗
PubMed2001

Cell surface events during resealing visualized by scanning-electron microscopy.

The function of exocytosis during plasma membrane resealing might be to facilitate the flow of surface lipid over the disruption site and/or to add defect-spanning "patches" of internal membrane across it. Scanning-electron-microscopic visualization of large plasma membrane disruptions in sea urchin eggs is here used to distinguish between these two possibilities. Disruptions were induced by shear stress in the presence and absence of resealing-permissive levels of external Ca2+, and the eggs were fixed at various intervals thereafter for microscopic processing. In eggs fixed immediately (<1 s) after shearing in the absence of Ca2+, a condition which prevents resealing, disruption sites were filled with a uniform population of spherical vesicles (approximately 1 microm in diameter). In eggs fixed immediately after shearing at a resealing-permissive level of Ca2+, disruption sites were filled with a highly heterogeneous population of enlarged vesicles, some being more than 10 microm in diameter and many having irregular profiles and/or appearing to be joined to one another. In eggs fixed 2 s or 5 s post-shearing, the continuity of these large vesicles with one another and the surface membrane began to obscure individual vesicle identities. Single "apertures" of discontinuity over disruption sites, the predicted morphology of a flow-based resealing mechanism, were not observed at any time point (1-5 s) during the interval required for completion of resealing. These observations provide strong confirmation that "patching" of large disruptions mediates their resealing.

Animals↗
PubMed2001

Randomized, controlled, bilateral (split-face) comparison trial of the tolerability and patient preference of adapalene gel 0.1% and tretinoin microsphere gel 0.1% for the treatment of acne vulgaris.

Poor patient compliance is one of the main reasons for treatment failure in acne. Our objective was to evaluate the tolerability and patient preference of adapalene gel 0.1% compared with tretinoin microsphere gel 0.1% using a randomized, controlled, investigator-masked, bilateral (split-face), 4-week comparative study of the 2 products when applied once daily in 40 patients. We found that adapalene produced less stinging/burning than tretinoin at weeks 1 and 4 and, overall, more patients felt more skin irritation on the side of the face treated with tretinoin than on the side treated with adapalene (P<.05). At week 4, a significantly greater number of patients preferred adapalene gel 0.1% to tretinoin microsphere gel 0.1% (72.5% vs 27.5%, respectively, P<.01).

Acne Vulgaris↗
PubMed2000

Patellofemoral pain syndrome in the female athlete.

Although PFS will continue to be a therapeutic challenge, the prognosis for most female athletes is good, especially if they are motivated and compliant with their treatment program. Particularly in women, care should be taken to avoid placing too much emphasis on biomechanical variants that may not be clinically significant or correctable because such findings can reinforce a feeling that "nothing can be done." In many cases, muscle dysfunction and repetitive loading of the patellofemoral joint rather than fixed biomechanical factors contribute to the development of PFS. Nonetheless, the importance of a detailed biomechanical assessment on physical examination must not be neglected, particularly in athletes who are not improving with conservative treatment and who may become surgical candidates. A practical initial treatment program for most athletes with nontraumatic PFS begins with relative rest, quadriceps strengthening, and stretching of tight myotendinous units. The introduction of NSAIDs, orthoses, taping, knee sleeves, and more specific rehabilitative exercises should be an individualized decision based on physical findings, past treatment results, and athletic expectations. Surgical referral should be considered in cases of PFS or patellar instability refractory to prolonged maximal nonoperative treatment.

Biomechanical Phenomena↗
PubMed1998

Anterior cruciate ligament injuries in the female athlete.

The normal anterior cruciate ligament (ACL) is critical to knee joint stability, especially for athletes in cutting sports. Rupture of the ACL can be a devastating, if not career-ending, injury for a young athlete because of the resultant instability and increased risk of meniscal and chondral damage. Considerably more girls and women than ever before now participate in athletics. Some epidemiologic data show that female athletes may sustain a higher incidence of ACL injuries than male athletes. Risk factors that may be responsible for these increased injury rates are reviewed. History and physical examination are most important in establishing the diagnosis of ACL injury, although ancillary diagnostic imaging is helpful if the extent of injury is in question. Treatment options, including various surgical reconstructions and rehabilitation, are discussed, with attention to the specific concerns of the female athlete. With appropriate diagnosis and treatment, the ACL-injured athlete may now anticipate full return to function and athletic competition.

Adolescent↗
PubMed1980

Immunochemical properties of abnormal hemoglobins C-Harlem (beta 6 Glu replaced by Val, beta 73 Asp replaced by Asn), S (beta 6 Glu replaced by Val), Korle Bu (beta 73 Asp replaced by Asn), Vancouver (beta 73 Asp replaced by Tyr), and Mobile (beta 73 Asp replaced by Val).

Antibodies were made to three mutant hemoglobins, each containing different single amino acid substitutions at beta 73:Hb Korle Bu (Asp replaced by Asn), Hb Mobile (Asp leads to Val), Hb Vancouver (Asp replaced by Tyr); and to one mutant hemoglobin, Hb C-Harlem, containing two substitutions in the beta chain (beta 6 Glu replaced by Val, as in Hb S, and beta 73 Asp replaced by Asn, as in Hb Korle Bu). The antiserum to Hb C-Harlem contained two antibody populations, each specific for one mutant amino acid residue. The antiserum to Hb Vancouver was completely specific for this mutant and did not cross-react with Hb Mobile and Hb Korle Bu; however, antiserum to Hb Korle Bu partially cross-reacted with Hb Mobile and to a smaller degree with Hb Vancouver. Antiserum to Hb Mobile exhibited even less cross-reactivity with Hb Korle Bu and C-Harlem and none with Hb Vancouver. These and previous studies indicate the involvement of at least three independent areas in the beta chain as antigenic determinant sites. It appears that the three mutants at beta 73 elicit the formation of antibodies which have a gradation in their specificity due to the nature of the amino acid sidechain.

Amino Acids↗
PubMed1978

Radioimmunochemical characterization of hemoglobins Lepore and Kenya: unique antigenic determinants located on hybrid hemoglobins.

Antisera were produced in rabbits to the three known types of Lepore hemoglobins, which contain hybrid delta-beta non-alpha-chains, and to hemoglobin Kenya, which has a hybrid gamma-beta non-alpha-chain. By using a sensitive radioimmunoassay technique, the absorbed antisera were shown to contain an antibody population that was specific for the hybrid hemoglobin and did not cross-react with normal hemoglobins. However, with the absorbed Lepore-specific antisera, the three known types of Lepore hemoglobins were antigenically indistinguishable from each other, suggesting that antibodies are not produced to the primary structural differences which define the three non-alpha-chains of the Lepore hemoglobins. These studies demonstrate that the non-alpha-subunits of hemoglobins Lepore and Kenya possess unique antigenic determinant sites, evidently resulting from an altered polypeptide conformation.

Animals↗
PubMed1976

Specific radioimmunochemical identification and quantitation of hemoglobins A2 and F.

Hyperimmune antisera to chromatographically purified hemoglobins F and A2 were produced in rabbits and made specific for the immunogen by adsorption with normal human hemoglobin A conjugated to cyanogen bromide-activated agarose. A radioimmunoassay was established that permitted identification and quantitation of each of these two minor hemoglobins in hemolysates containing other hemoglobin components. The quantities of hemoglobins A2 and/or F present in hemolysates of individuals with beta-thalassemia, sickle cell anemia, Hb-C disease, and other hematological disorders were determined immunochemically, and the results were commpared to values obtained by microcolumn chromatography for the measurement of Hb-A2 or with the alkali denaturation technique in quantitating Hb-F. The immunoassay procedure has a greater sensitivity than other commonly employed techniques and can detect as little as 0.05 mug of these hemoglobins.

Animals↗