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Biomedical subjects

S Pfeiffer

Publications and source records attributed to S Pfeiffer.

At least 91 records · Page 5Linked to original sources
PubMed1992

Cortical bone age estimates from historically known adults.

Adult skeletal remains from 19th century historic cemeteries were used to test the accuracy and precision of age estimations based on the cortical bone histological technique proposed by Thompson [6, 7]. Comparison of estimates made from anterior microscopic fields versus peripheral fields (N = 29 femora) indicates general age agreement, with 6/29 demonstrating marked differences between sampling locations. Three cases of unilateral trauma show no consistent effect on bone age estimates. Among sixteen adults of known age, the ages of eight were accurately estimated; five were estimated to be significantly older and three were estimated to be younger than they were. It is argued that cortical erosion/diagenetic destruction may contribute to overestimation by obscuring the periosteal regions required for application of the technique. While not without its shortcomings, it is concluded that the Thompson technique is relatively robust and merits further development.

Adolescent↗
PubMed1991

Variation in estrus-related odors in the cow and its dependency on the ovary.

Urine samples were collected from 10 cows during the estrous cycle (Day 0=day of observed estrus) and investigated for pheromone activity using a quantitative rat bioassay. Pheromone activity in this assay was given in impulses/45 sec. Progesterone was measured in milk fat to verify the stage of cycle. The maximal response of rats was found on Day -1 (20.0 +/- 3.5 impulses/45 sec; x +/- SEM), and impulse rates were clearly higher (P <or= 0.001) than in the diestrous urine samples (5.2 +/- 0.7 impulses/45 sec) from Day -2 to Day +2. A negative correlation (r = -0.34; P <or= 0.001) was found between progesterone concentrations and impulse rates. The dependence of pheromone activity on estradiol was investigated in urine samples from six ovariectomized cows collected before and after estradiol administration. In all cows estradiol led to clear estrous symptoms, but it did not induce pheromone activity in urine. It is concluded that the appearance of maximal pheromone activity one day before estrus signals the imminence of estrus to the bull. The presence of the ovary seems to be essential for the synthesis of the pheromone, and an estrogen-dependent source outside the ovary is unlikely.

Journal Article↗
PubMed1990

Endothelial cell toxicity of solid-organ preservation solutions.

Endothelial cell damage caused by myocardial cardioplegic solutions (Bretschneider HTK and St. Thomas' Hospital No. 2) or renal and hepatic cold storage solutions (modified Collins and University of Wisconsin solution) was assessed in monolayer cultures of adult human venous endothelial cells at 4 degrees to 10 degrees C with phase-contrast microscopy. St. Thomas' Hospital solution caused the cells to contract, resulting in disruption of monolayer integrity and opening of intercellular gaps, and resulted in a 24-hour postexposure survival of 51.0% +/- 2.4%. Bretschneider HTK solution altered cellular morphology less and produced the best postexposure survival (80.2% +/- 2.6%; p less than 0.001). Although morphology was altered the least with University of Wisconsin solution, postexposure survival with this solution, which was similar to that with modified Collins solution, was superior to that with St. Thomas' (p less than 0.01) but inferior to that with Bretschneider HTK (p less than 0.05). The superior protection provided by Bretschneider HTK was due to its additives histidine, tryptophan, and KH-2-oxygluterate (p less than 0.005), and to its low chloride content (p less than 0.005). Furthermore, modifying St. Thomas' solution by decreasing its chloride content improved cell survival to 71.2% +/- 2.3% (p less than 0.001). Normothermic (37 degrees C) exposure to Bretschneider HTK, modified Collins, and University of Wisconsin solution was cytotoxic, whereas normothermic exposure to St. Thomas' cardioplegia was not. In conclusion, the preservation solution that is the least harmful to endothelial cells at hypothermia is Bretschneider HTK cardioplegic solution.

Adenosine↗
PubMed1989

The dynamic nature of the Golgi complex.

The intracellular transport of newly synthesized G protein of vesicular stomatitis virus is blocked at 20 degrees C and this spanning membrane glycoprotein accumulates in the last Golgi compartment, the trans Golgi-network (TGN). Previous morphological evidence suggested that the TGN enlarged significantly under this condition. In the present study we have used stereological procedures to estimate the volume and surface area of the Golgi stack and the TGN of baby hamster kidney cells under different conditions. The results indicate that the increase in the size of the TGN at 20 degrees C is accompanied by a significant decrease in the surface area and volume of the preceding Golgi compartments. A similar effect is also seen in uninfected cells at 20 degrees C, as well as during normal (37 degrees C) infection with Semliki Forest virus. In the latter case, however, the decrease in the size of the Golgi stack and the increase in that of the TGN is not accompanied by inhibition of transport from the Golgi complex to the cell surface. The results indicate that the Golgi stack and the TGN are dynamic and interrelated structures that are capable of rapid alteration in total surface area in response to changes in the rates of membrane transport.

Animals↗
PubMed1985

Intracellular sorting and basolateral appearance of the G protein of vesicular stomatitis virus in Madin-Darby canine kidney cells.

The polarity of the surface distribution of viral glycoproteins during virus infection has been studied in the Madin-Darby canine kidney epithelial cell line on nitrocellulose filters. Using a surface radioimmunoassay on Madin-Darby canine kidney strain I cells that had been infected with vesicular stomatitis virus or with avian influenza fowl plague virus, we found that the surface G protein was 97% basolateral, whereas the fowl plague virus hemagglutinin was 88% apical. Newly synthesized, pulse-labeled vesicular stomatitis virus appeared first on the basolateral plasma membrane as measured by an immunoprecipitation assay in which the anti-G protein antibody was applied to the monolayer either from the apical or the basolateral side. Labeled G protein could be accumulated inside the cell at a late stage of transport by decreasing the temperature to 20 degrees C during the chase. Reversal to 37 degrees C led to its rapid and synchronous transport to the basolateral surface at an initial rate 61-fold greater than that of transport to the apical side. These results demonstrate that the newly synthesized G protein is transported directly to the basolateral membrane and does not pass over the apical membrane en route. Since a previous study of the surface appearance of influenza virus hemagglutinins showed that the newly synthesized hemagglutinins were inserted directly from an intracellular site into the apical membrane (Matlin, K., and K. Simons, 1984, J. Cell Biol., 99:2131-2139), we conclude that the divergence of the transport pathway for the apical and basolateral viral glycoproteins has to occur intracellularly, i.e., before reaching the cell surface.

Animals↗
PubMed1985

Exit of newly synthesized membrane proteins from the trans cisterna of the Golgi complex to the plasma membrane.

The intracellular location at which the G protein of vesicular stomatitis virus accumulated when transport was blocked at 20 degrees C has been studied by biochemical, cytochemical, and immunocytochemical methods. Our results indicated that the viral G protein was blocked in that cisterna of the Golgi stack which stained for acid phosphatase. At 20 degrees C this trans cisterna became structurally altered by the accumulation of G protein. This alteration was characterized by extensive areas of membrane buds which were covered by a cytoplasmic coat. These coated structures were of two kinds--those that labeled with anti-clathrin antibodies and those that did not. The clathrin-coated pits consistently did not label with anti-G antibodies. Upon warming infected cells to 32 degrees C, G protein appeared on the surface within minutes. Concomitantly, the trans cisterna lost its characteristic structural organization. Double-labeling experiments were performed in which G protein localization was combined with staining for horseradish peroxidase, which had been taken up from the extracellular medium by endocytosis. The results suggest that the trans cisterna was distinct from the endosome compartment and that the latter was not an obligatory station in the route taken by G protein to the cell surface.

Animals↗
PubMed1984

Paleopathology in an Iroquoian ossuary, with special reference to tuberculosis.

Pathological skeletal remains from the Uxbridge Ossuary (1490 +/- 80 A.D., N = 457) are classified into four broad categories: trauma, congenital disability, tumor, and infection. Traumatic injuries are relatively common (fractures in 5-9.4% of total), considering the date and subsistence pattern of the population. Congenital disabilities and tumors are rare, affecting approximately 2% of the population. Nonspecific periosteitis and osteitis affect 5% of the sample. By far the most common pathological skeletal changes are lytic lesions leading to cavitation of cancellous bone, especially in the lower vertebral and sacro-iliac regions. It is argued that the changes seen and their distribution are most consistent with a diagnosis of tuberculosis. Applying clinical observations regarding bone involvement, it is estimated that a minimum of 26 skeletons were affected. This in turn indicates a very high population tuberculosis incidence. The Uxbridge sample is neither the only nor the earliest Iroquoian ossuary to display apparent tuberculosis (Hartney 1981). The common presence of this disease in some communities and its low incidence in others are discussed in the context of the epidemic wave phenomenon. There is strong evidence for warfare at Uxbridge, and this warfare may have produced crowding, poor hygiene and diet, such that the disease could flourish.

Adolescent↗
PubMed1983

Cortical bone formation and diet among protohistoric Iroquoians.

Two samples of protohistoric Iroquoians are found to show low values for bone formation indicators. Two southern Ontario ossuary samples, Kleinburg (1600 AD, N = 561) and Uxbridge (1490 +/- 80 AD, N = 457) are examined. Mean values for the cortical index (Barnett and Nordin, 1960) and percent cortical area (Garn, 1970) are consistently below expected normal values. Some of the lowest values may reflect the presence of a disease state. Nevertheless, it is argued that the results may indicate chronic dietary insufficiencies. Both absolute calcium intake and the calcium to phosphorous ratio are discussed as possible causative factors.

Adult↗
PubMed1983

Stem cells and immunological parameters in mice during the latency period and after the development of chemically induced leukemia.

T-cell leukemias have been induced in adult BDF1 mice by 12 or 15 weeks of exposure to butylnitrosourea (BNU) in the drinking water. This led to a depression of CFU-S numbers and reduced T- and B-cell responses to mitogens. These parameters were then studied during the BNU-free preleukemic latency period in individual mice. At the same time, leukemic cells were traced in the thymus, the spleen, and the bone marrow by transplantation. In mice without leukemia and mice with leukemic cells in only one organ, there was a general tendency to normal CFU-S numbers and T- and B-cell responses with time after BNU, although control levels were reached in only a few of the mice. The reaction of mixed lymphocyte cultures (MLC) remained low during the latency period. In the thymus an imbalance of the Con A, PHA, and MLC responses was observed. Out of 25 mice with induced leukemia, 8 had leukemic cells in the thymus only and 2 in the marrow only. In mice with leukemic cells in all 3 hemopoietic organs and an enlargement of the spleen, a shift of CFU-S from the marrow to the spleen was observed.

Animals↗
PubMed1980

Age changes in the external dimensions of adult bone.

Humeri from a large, ossuary-derived sample are used to demonstrate that considerable size variability is introduced to transverse skeletal measurements when young adults and older adults are pooled. Humeri from young adults (epiphyseal lines still visible, N approximately 25) are smaller in transverse dimensions than those of older adults (N approximately 300). Among left humeri, only shaft diameters demonstrate statistically significant differences. The right humeri, however, show statistically significant differences for six of the eight measurements. The increased size of the older adult humeri reflects the fact that appositional growth continues throughout adulthood. The more pronounced differences seen on the right side probably reflect developing dominance asymmetry. Recognition of this source of intrasample variability will influence the choice of skeletal measurements used for population comparisons and/or indicators of robusticity.

Adult↗
PubMed1978

The relationship of buccal pits to caries formation and tooth loss.

It is demonstrated that in mandibular molars there is a statistically significant tendency for teeth with buccal pits to be lost premortem more frequently than teeth without buccal pits. The mandibles of a large ossuary population (ca. 1600 A.D.) are examined with regard to buccal pitting, caries formation and premortem tooth loss. A log likelihood ratio test is used to test the relationship between age and frequency of buccal pits. A G-value of 20.84 (p less than 0.025) indicates that the frequency of pits is significantly higher among individuals under ca. 18 years. It is argued that caries formation is the mechanism through which the molars are lost, given high caries frequencies that approximate pitting frequencies in their distribution.

Age Factors↗