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Biomedical subjects

D Glaser

Publications and source records attributed to D Glaser.

At least 37 records · Page 2Linked to original sources

Rate of metabolism in the smallest simian primate, the pygmy marmoset (Cebuella pygmaea).

Rate of metabolism was measured with six adult pygmy marmosets (Cebuella pygmaea) at regulated ambient temperatures ranging between 20 degrees C and 35 degrees C. A novel combined nest box and metabolic chamber was designed to allow nighttime measurements on immobile animals in their home cage without disturbance. The basal rate of metabolism (BMR) was 98 ml O2 h-1, representing 74% of the value expected from the equation of McNab [Quarterly Review of Biology 63:25-54, 1988] relative to body mass. The thermoneutral zone was approximately 27-34 degrees C. Below the lower critical temperature (27-28 degrees C), thermal conductance (12.9 ml O2 h-1 degree C-1) was close to the predicted value. Body temperature ranged between 34.9 degrees C and 35.5 degrees C at night. When two animals rested together overnight in the nest box, the lower critical temperature was slightly lowered, and individual energy expenditure at 20-21 degrees C was reduced by about 34%. The basal rate of metabolism of C. pygmaea is much lower than reported in an earlier study based on daytime measurements but agrees with values reported from a more recent study conducted at night with a classical metabolic chamber. In order to compare the BMR of C. pygmaea with that of other primates, 23 species were included in a comparative study taking into account both phylogeny and body mass (independent contrasts approach). The scaling exponent of BMR to body mass obtained was indistinguishable from that published for eutherian mammals in general. Cebuella and Callithrix exhibit the lowest basal rates known for simians. This trait may possibly be linked to the natural diet, which includes a large proportion of gums that are difficult to digest, but additional metabolic studies on primates are needed for further examination of its adaptive significance.

Animals↗

Evolution of the sweetness receptor in primates. II. Gustatory responses of non-human primates to nine compounds known to be sweet in man.

The gustatory responses of nine compounds, namely glycine, D-phenylalanine, D-tryptophan, cyanosuosan, magapame, sucrononate, campame, cyclamate and superaspartame, all known as sweet in man, were studied in 41 species or subspecies of non-human primates, selected among Prosimii (Lemuridae and Lorisidae), Platyrrhini (Callitrichidae and Cebidae) and Catarrhini (Cercopithecidae, Hylobatidae and Pongidae). The first six compounds are generally sweet to all primates, which implies that they interact with the primate sweetness receptors essentially through constant recognition sites. Campame is sweet only to Cebidae and Catarrhini, cyclamate only to Catarrhini, superaspartame principally to Callitrichidae and Catarrhini, which implies that all these compounds interact with the receptors partly through variable recognition sites. From the present work, from other previous results (where notably it was observed that alitame is sweet to all primates, ampame only to Prosimii and Catarrhini, and aspartame only to Catarrhini), and from the multipoint attachment (MPA) theory of sweetness reception (as elaborated by Nofre and Tinti from a detailed study of structure-activity relationships of various sweeteners in man), it is inferred that the primate sweetness receptors are very likely made up of eight recognition sites, of which the first, second, third, fourth, seventh and eighth are constant, and the fifth and sixth variable. From these results and from the MPA theory, it is also inferred that the recognition sites of the primate sweetness receptors could be: Asp-1 or Glu-1, Lys-2, Asp-3 or Glu-3, Thr-4, X-5, X-6, Thr-7, Ser-8, where the variable recognition sites X-5 and X-6 would be: Ala-5 and Ala-6 for Callitrichidae, Ser-5 and Ala-6 for Cebidae, Ala-5 and Thr-6 for Prosimii, and Thr-5 and Thr-6 for Catarrhini. By using Tupaiidae (tree shrews) as a reference outgroup and by means of other structural and functional molecular considerations, it appears that Callitrichidae have retained the most primitive receptor among the four types of primate receptors. The possible taxonomic and phylogenetic implications of these findings are discussed.

Animals↗

500 FBI agents.

Explore the source record for details and available documents.

Accounting↗

Immunolocalization and expression of bone morphogenetic proteins 2 and 4 in fracture healing.

Recently, it has become increasingly evident that fracture healing involves a complex interaction of many local and systemic regulatory factors. The roles of some of these growth factors have been described; however, little is understood about the presence of the bone morphogenetic proteins in fracture repair, despite the fact that they are the most potent osteoinductive proteins known. This study defines and characterizes the physiologic presence, localization, and chronology of the bone morphogenetic proteins in fracture healing with an established rat fracture healing model. With use of a recently developed monoclonal antibody against bone morphogenetic proteins 2 and 4 developed with standard avidin-biotin complex/immunoperoxidase protocols, frozen undecalcified fracture calluses were analyzed semiquantitatively for the percentage of various types of fracture cells staining positively. During the early stages of fracture healing, only a minimum number of primitive cells stained positively in the fracture callus. As the process of endochondral ossification proceeded, the presence of bone morphogenetic proteins 2 and 4 increased dramatically, especially in the primitive mesenchymal and chondrocytic cells. While the cartilaginous component of the callus matured with a concomitant decrease in the number of primitive cells, there was a concomitant decrease in both the intensity and the number of positively staining cells. As osteoblasts started to lay down woven bone on the chondroid matrix, these osteoblastic cells exhibited strong positive staining. The intensity of this staining decreased, however, as lamellar bone replaced the primitive woven bone. A similar observation was noted for the areas of the callus undergoing intramembranous ossification. Initially, within several days after the fracture, periosteal cells and osteoblasts exhibited intense staining for bone morphogenetic proteins 2 and 4. As the woven bone was replaced with mature lamellar bone, this staining decreased. These data, and the awareness of the strong osteoinductive capacities of bone morphogenetic protein, suggest that bone morphogenetic proteins 2 and 4 are important regulators of cell differentiation during fracture repair.

Animals↗

Evolution of the sweetness receptor in primates. I. Why does alitame taste sweet in all prosimians and simians, and aspartame only in Old World simians?

In the order Primates the responses to sucrose, alitame and aspartame were ascertained. All primates tested to date like sucrose and prefer this sweet substance to tap water. The artificial dipeptide aspartame was found to be not sweet in Prosimii and Platyrrhini (New World monkeys). Only the Cercopithecoidea (Old World monkeys) and Hominoidea (apes and humans) show the same response to aspartame and to sucrose. In contrast, all primates tested so far prefer alitame, another artificial dipeptide sweetener, which is structurally closely related to aspartame. This phylogenetic difference is consistent with the existence in catarrhine primates of a sweetness receptor containing two differently located hydrophobic recognition sites, one for the hydrophobic binding site of alitame, the other for the hydrophobic binding site of aspartame. On the basis of these results, it is suggested that the alitame-related hydrophobic recognition site, which is found in the sweetness receptor of all primates, could be a requisite for the interaction of the receptor with sucrose, while the aspartame-related hydrophobic recognition site, which is found exclusively in the sweetness receptor of Old World simians, could have been a crucial factor in the improvement in detection or selection of sucrose in foods, so favouring the mental development of these simians and maybe the emergence of humans.

Animals↗

Alternatives to Autogenous Bone Graft: Efficacy and Indications.

Bone grafting is frequently used to augment bone healing with the numerous approaches to reconstructing or replacing skeletal defects. Autologous cancellous bone graft remains the most effective grafting material because it provides the three elements required for bone regeneration: osteoconduction, osteoinduction, and osteogenic cells. Autologous cortical bone graft provides these three components to a limited extent as well and also provides the structural integrity important in reconstruction of larger defects. However, because autogenous grafting is associated with several shortcomings and complications, including limited quantities of bone for harvest and donor-site morbidity, alternatives have been used in a wide range of orthopaedic pathologic conditions. Grafting substitutes currently available include cancellous and cortical allograft bone, ceramics, demineralized bone matrix, bone marrow, and composite grafts. No single alternative graft material provides all three components for bone regeneration. The clinical applications for each type of material are dictated by its particular structural and biochemical properties. Composite grafts consisting of several materials are often used to maximize bone healing, especially where the grafting site is compromised.

Journal Article↗

Stark self-referral law.

Should Iowa physicians worry about the Stark law? Probably. In September, after a nearly four-year delay, the regulations for Stark I took effect. This article discusses how the Stark I and II self-referral laws might affect your practice.

Iowa↗

[Postmenopausal virilization in thecosis of the ovaries].

We describe the case of a 74-year-old woman with a fifteen-year old history of virilism and with a Type-II-diabetes mellitus treated with insulin. After the removal of the ovaries, the formerly elevated serum-testosterone levels normalised and the signs of virilism gradually abated. The histological finding of stromal thecosis in the ovaries is discussed in relation to hyperinsulinaemia and other potential stimuli for ovarian stromal hyperplasia.

Aged↗

[Ovarian cancer in ovarian remnant syndrome?].

We report on a malignant pelvic tumour in a 69-year old woman, whose uterus and adnexa had been removed 22 years ago because of endometriosis. Clinical and pathological findings pointed to an ovarian cancer in an ovarian remnant syndrome. In a case of a carcinoma, it is difficult to furnish proof of an ovarian remnant syndrome. Differential diagnoses, especially the ureteral adenocarcinoma, are discussed.

Adenocarcinoma, Papillary↗

Treatment issues in child sexual abuse.

Child sexual abuse is a commonly encountered and often emotionally damaging experience, maintained by secrecy and followed by denial after disclosure. Treatment in this field involves both the child and the family in a variety of treatment settings and modalities, often proceeding in parallel. Child developmental considerations dictate that treatment often proceeds in phases. It aims to protect the child from further abuse and the consequences of disclosure, and address the trauma and context of the abuse. Careful planning and co-operation is required by the many professionals working in this stressful area in order to avoid confusion, conflicts, and splits which may mirror relationships in the family. The heterogeneity of the problem is reflected in the fact that treatment cannot be offered in a uniform programme. Legal issues may influence the treatment process. Evaluation of treatment modalities, the identification of protective factors and achieving long-term adjustment in the least detrimental manner offer challenges in this newly developing field.

Adaptation, Psychological↗

Relationship between changes in buoyant density and formation of new sites of cell wall growth in cultures of streptococci (Enterococcus hirae ATCC 9790) undergoing a nutritional shift-up.

When the glutamate concentration of cultures of Enterococcus hirae was raised from 20 to 300 micrograms/ml, the mass doubling time decreased from ca. 85 to 45 min in 9 min, but balanced growth was not reestablished for 30 to 40 min. During the unbalanced period of growth, RNA and protein synthesis proceeded more rapidly than did peptidoglycan synthesis, buoyant density increased from ca. 1.1024 to 1.1075 g/ml, and the rate of formation of new cell wall growth sites transitorily accelerated above the new growth rate. When studied as a function of cell size, all cultures showed buoyant density to decrease around cell separation, increase as cells increased in size, and then plateau when cells reached large volumes. Greater increases in buoyant density as a function of cell size were seen after shift-up, with the greatest increases observed at 15 to 20 min after shift-up, when the rate of formation of new sites was also maximal. In a population of cells examined by electron microscopy 15 min after shift-up, buoyant density and the frequency of cells with new sites increased as old sites approached the size of two poles. These data were consistent with a model whereby buoyant density increases in the terminal stages of the cell cycle when the surface grows slower than the cytoplasm. The greater the difference in the rates of inside to outside growth, the greater the increase in buoyant density and the more frequently new sites will be initiated.

Cell Wall↗