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Biomedical subjects

S C Marks

Publications and source records attributed to S C Marks.

At least 73 records · Page 4Linked to original sources
PubMed1997

Zinc deficiency in head and neck cancer patients.

BACKGROUND: Although a great deal of attention has been given to protein and calorie malnutrition in patients with head and neck cancer, zinc status has not been assessed properly in such patients in the past. METHODS: In this study we characterized zinc status by cellular zinc criteria and assessed several measures of protein and calorie malnutrition in patients with head and neck cancer. We determined prognostic nutritional index (PNI) based on serum albumin, serum transferrin, triceps skin fold measures, and delayed hypersensitivity, as proposed by Buzby et al. In this study, the baseline zinc status and PNI of 60 head and neck cancer patients were correlated with the tumor size and overall stage of the disease. RESULTS: Our results showed that the tumor size and overall stage correlated significantly to zinc status whereas no correlation was seen with PNI, alcohol intake, or smoking in our study subjects. CONCLUSION: We conclude that zinc status is a better indicator of tumor burden and stage of the disease in head and neck cancer patients than the patients' overall nutritional status.

Aged↗
PubMed1997

Acute sinusitis in the rabbit: a new rhinogenic model.

The objective of this study was to create a rhinogenic model of sinusitis using an implanted foreign body in the nasal cavity of the rabbit. The study design was a prospective controlled trial of the experimental design. In this model an obstructing foreign body was placed into the nasal cavity and then impregnated with pathogenic bacteria. This model was studied histologically using whole-mount techniques. Quantitative assessment of the degree of inflammation was made for the maxillary and ethmoid sinus and for overall effect for each animal. Bacteriologic study was performed in a limited number of animals. The results indicated that a significant infection develops in about half of animals. This peaks in intensity between 1 and 2 weeks after implantation and subsequently subsides with some evidence of long-term changes present after 4 weeks. It is concluded that this is a viable and perhaps preferable animal model to study sinusitis. Further investigation is necessary to completely characterize this model.

Acute Disease↗
PubMed1997

The microvenous valvular anatomy of the human dorsal thoracic fascia.

The use of free scapular fasciocutaneous flaps for reconstruction of recalcitrant grade 6 venous stasis ulcers has shown excellent early success rates. Venous refilling times measured postoperatively over the flaps by photoplethysmography have noted improvements to normal levels. Preliminary anatomic studies have demonstrated valves in the circumflex scapular veins of flaps used in reconstruction. The purpose of this study was to investigate and document the number, morphology, size, and location of valves in the human dorsal thoracic fascia. Ten scapular flaps were obtained from unembalmed cadavers and injected with methyl methacrylate. Each flap cast was divided into four parts: proximal, right and left, and distal, right and left. We reduced the size of specimens (the largest being 24 x 11 mm) and studied them in a scanning electron microscope. We identified all valves, estimated the diameter of the corresponding vein, calculated the depth of the valvular sinus, and related it to the corresponding venous size. Light microscopy and transmission electron microscopy were used as assisting tools applied to glutaraldehyde-fixed specimens. Analysis of injected specimens showed that valves were most abundant in veins with a luminal diameter of 30 to 120 microns (59.3 percent of 905 valves). The depth of valves became larger with increasing venous diameter. The sizes of valve sinuses were not different for individual valves. Except for veins larger than 1000 microns in diameter, there was no significant difference between the number of valves in different parts of an individual flap, nor were there significant differences between the valve numbers in different flaps. Most valves were bicuspid; only in the vein category of 30 to 120 microns were unicuspid valves encountered. Valves sometimes were located in series in a short segment of a vein; occasionally, they were found at the merging site of two veins. Transmission electron microscopy showed that valve leaflets had collagen fibers that ascended toward the tip of the leaflet and occasionally were accompanied by elastic fibers. Myofibroblasts were regularly present in the valve leaflets. These data show that fasciocutaneous flaps from the scapular region have numerous valves (90 valves on average in each flap) in the venous microcirculation. The microvenous valves in the dorsal thoracic fascia appear to be structurally similar to valves in larger veins. These valves may play a role in the improved hemodynamics and promising clinical outcome of patients with chronic venous insufficiency who have undergone free scapular flap reconstruction.

Fascia↗
PubMed1997

Medial border of the perirenal space: CT and anatomic correlation.

PURPOSE: To explore the mode of spread of disease between the perirenal space and the perivascular central retroperitoneum and to determine the anatomy along the medial border of the perirenal space. MATERIALS AND METHODS: Anatomic dissection, injection of latex, and observation of cross sections of the abdomen were performed in nine cadavers. Attention was paid to the juncture of the central prevertebral, perivascular, and extraperitoneal regions, and the perirenal space. Anatomic findings were correlated with observations made at computed tomography (CT) in 82 patients with retroperitoneal hemorrhage (n = 24), inflammation (n = 37), and neoplasia (n = 21) involving the perirenal spaces or the central retroperitoneum. RESULTS: Along most of the length of each kidney, no apparent fascia separates the perirenal space from the central retroperitoneum. At this location, septa between fat lobules form a fenestrated multitier barrier. These septa were imperceptible on CT scans obtained in healthy individuals. After injection of latex in cadavers, this potential barrier was seen. In the clinical study, spread of disease was allowed in only 38 (30%) of 128 instances of potential spread. Spread was facilitated along the renal vessels and the interlobular septa. CONCLUSION: Beyond the kidneys, the renal fascia is closed, forming a cone superiorly and an inverted cone inferiorly. A network of interlobular septa acted as a barrier or pathway to the free spread of disease from the perirenal space to the central retroperitoneum or from the central retroperitoneum to the perirenal space.

Adult↗
PubMed1997

Monocyte recruitment and expression of monocyte chemoattractant protein-1 are developmentally regulated in remodeling bone in the mouse.

Tooth eruption is defined as the movement of a tooth from its site of development within the alveolar bone to its position of function in the oral cavity. It represents an excellent model to examine osseous metabolism as bone resorption and bone formation occur simultaneously and are spatially separated. Bone resorption occurs in the coronal (occlusal) area, whereas bone formation occurs in the basal area. Monocytes are thought to have a significant role in the regulation of osseous metabolism. The goal of this study was to examine the recruitment of monocytes to bone in C57BL/6J mice that are undergoing developmentally regulated bone remodeling. Monocytes were detected by immunohistochemistry and osteoclasts were counted as bone-associated multi-nucleated, tartrate-resistant acid phosphatase (TRAP)-positive cells. Cell numbers were obtained from histological sections of animals sacrificed daily for 14 days after birth; an image analysis system was used for quantification. The results demonstrated that, immediately after birth, there were relatively few monocytic cells. In the area of bone resorption, the number of monocytes increased with time, reaching peaks at 5 and 9 days, and decreased thereafter. A similar pattern was observed for osteoclasts. In the area of bone formation, there was a time-dependent increase in the number of monocytes. In contrast, the number of osteoclasts in this area was highest at the earliest time points and decreased after day 3. To investigate potential mechanisms for the recruitment of monocytes, expression of monocyte chemoattractant protein (MCP)-1 was assessed. The number of MCP-1-positive cells increased with time and was generally proportional to the recruitment of mononuclear phagocytes. Osteoblasts were the principal bone cell type expressing MCP-1. The results demonstrate that the recruitment of mononuclear cells in the occlusal area is associated with bone resorption. In contrast, recruitment of monocytes in the basal area is associated with bone formation and a decrease in the number of osteoclasts. These results suggest that monocytes have different functional roles in areas of bone formation compared with bone resorption. Furthermore, the expression of MCP-1 is developmentally regulated and may provide a mechanistic basis to explain the recruitment of monocytic cells.

Animals↗
PubMed1997

Cellular and molecular strategies for studying the regulation of bone resorption using the toothless (osteopetrotic) mutation in the rat.

The division of labor among cells of the skeleton is distinct and diverse and the regulation of these cells is interdependent. Osteoclasts are the cellular source of bone resorption and signals for their development and activation come, at least in part, from bone and other cells in the local environment. Studies of isolated cells have identified some factors in the developmental cascade of osteoclasts but there is little understanding of the sequence and local concentrations, not to mention other factors, needed for both the development of competent osteoclasts and for coordinated bone resorption. We review the skeletal biology of one osteopetrotic mutation in the rat, toothless, in which bone resorption is severely reduced because of a failure in the development and function of osteoclasts. Furthermore, we review the advantages and limitations of a relatively new method, differential display of mRNA (DD), that identifies differences in gene expression in two or more populations of cells. We present a strategy and preliminary data for the application of DD to this mutation. We propose that application of this method to these and other skeletal diseases, with the appropriate controls and confirmations, will provide data about pathogenetic pathways and has a high probability for identifying new regulators of skeletal development and turnover.

Animals↗
PubMed1996

Bone surface morphology reflects local skeletal metabolism.

The metabolic activity of bone cells is faithfully reflected in the surface topography of mineralized bone surfaces, and this can be easily detected by scanning electron microscopy (SEM). Forming bone surfaces exhibit knobby projections which represent foci of mineralization, resorbing surfaces are scalloped, and resting surfaces undergoing neither activity are smooth, as shown by Boyde and Hobdell 25 years ago. These phenomena are illustrated in vivo by tooth eruption, a local activity in alveolar bone where resorption and formation are polarized around an erupting tooth, and osteopetrosis, a metabolic bone disease characterized by a congenital reduction or absence of bone resorption. The ability to analyze bone metabolism over large areas of the skeleton by SEM offers a convenient and powerful microscopic technique to assess regional and global bone cell activity in an era where the investigative focus is increasingly molecular.

Animals↗
PubMed1996

Use of bone cell cultures to study skeletal pathology.

We describe procedures for the isolation, culture, and analysis of neonatal osteoblasts from osteopetrotic (toothless (tl) and osteopetrosis [op]) rats and normal littermates. Normal osteoblasts produce and mineralize an extracellular matrix indistinguishable from that of well-characterized fetal rat osteoblasts in vitro. Mutant (tl and op) cultures show an early abnormal pattern of cell proliferation and a later premature, extensive mineralization which mimic the mutant phenotype in vivo. In cocultures with normal osteoclasts, mutant (tl) osteoblasts also show a greatly reduced ability to orchestrate bone resorption, as revealed by pit formation in bone slices, in response to physiologic mediators. These phenomena in vitro are consistent with the behavior of mutant osteoblasts and osteoclasts in vivo and suggest that more definitive microscopic analyses of osteoblasts from each mutation in vitro will provide insights on the roles of osteoblasts in the compromised bone resorption which characterizes the osteopetroses as well as their role in osteoclast ontogeny. This study shows that when their behavior is confirmed in vivo, bone cell cultures offer rigorous systems for understanding skeletal cell dysfunction in normal and pathological development.

Animals↗
PubMed1996

Cytomegalovirus sinusitis. A new manifestation of AIDS.

Cytomegalovirus is a common pathogen in patients infected with the human immunodeficiency virus. In this article, cytomegalovirus sinusitis is described and documented for the first time, to our knowledge. Cytomegalovirus was cultured from the sinuses of four patients who were positive for the human immunodeficiency virus and who had antibiotic-resistant infections. In one patient who underwent surgery, cytomegalovirus inclusions were documented consistent with invasive infection. Optimal treatment has yet to be determined, but in this case surgery did provide temporary relief of sinus symptoms.

AIDS-Related Opportunistic Infections↗
PubMed1996

Tooth eruption: theories and facts.

The mechanisms of tooth eruption (i.e., the answer to the question of how and why teeth erupt) has been a matter of long historical debate. This review focuses on human and other mammalian teeth with a time- and spacewise limited period of eruption and analyzes recent observations and experimental data on dogs, rats, primates, and humans in a framework of basic biological parameters to formulate a guiding theory of tooth eruption. Acknowledging basic parameters (i.e., that teeth move in three-dimensional space, erupt with varying speed, and arrive at a functional position that in inheritable) eliminates a number of previously held theories and favors those that accommodate basic parameters, such as alveolar bone remodeling in association with root elongation, with possible correction factors in the form of cementum apposition and periodontal ligament formation. We have critically analyzed, summarized, and integrated recent findings associated with preeruptive movements of developing teeth, the intraosseous stage of premolar eruption in dogs, molar eruption in rodents, and premolar and molar eruption in primates. The variable speeds of eruption are particularly important. We conclude with basic principles of tooth eruption--that is, the type of signals generated by the dental follicle proper, the conditions under which teeth are moved and the clinical understanding to be derived from this knowledge.

Animals↗
PubMed1996

Heterogeneity of colony stimulating factor-1 gene expression in the skeleton of four osteopetrotic mutations in rats and mice.

Congenital osteopetrosis in mammals is an inherited bone disease caused by aberrations in osteoclast development and/or function. Colony-stimulating factor-1 (CSF-1) promotes formation of osteoclasts and is produced by osteoblasts. Recently, two osteopetrotic mutations (op mouse and tl rat) have been shown to have reductions in CSF-1 activity, and CSF-1 injections improve the skeletal manifestations in each. Several different CSF-1 transcripts have been described in mouse and human soft tissues, and differential expression of CSF-1 transcripts has been documented. Thus, we compared gene expression for CSF-1 as reflected by mRNA levels in the bones of tl rats and op mice, and also two other osteopetrotic rat mutations (ia and op). In op mouse calvaria the 4.6 kb transcript was reduced while the 2.3 kb transcript was absent. However, no differences were detected in the levels of these transcripts in mutant and normal calvaria of tl stock. In contrast, CSF-1 transcript levels were elevated in op rat mutants and variable in ia mutants compared to normal littermates. Osteoblast cultures derived from neonatal animals of tl and op rat stock showed the same differences seen in calvarial bone in vivo. The mRNA expression of another growth factor, TGF-beta 1, paralleled that of CSF-1 in vivo and in vitro in the rat mutations. These data demonstrate the emerging molecular heterogeneity among osteopetrotic mutations and underscore the need to evaluate the contributions of these and other cytokines to osteoclast differentiation and function in each mutation.

Animals↗
PubMed1996

Human osteoclast-like cells in primary culture.

We describe a method for the isolation and culture of osteoclast-like cells from cancellous bone chips of iliac crests from patients undergoing reconstructive maxillofacial surgery. Under aseptic conditions, bone chips were cut into small pieces, incubated briefly with collagenase, and the isolated bone cells were separated from the bone chips by filtration using a nylon mesh. Bone cells were then cultured on a variety of surfaces for up to 10 days. Cell motility and fusion, together with the development of tartrate-resistant acid phosphatase activity, were seen in many cells soon after culture. The large osteoclast-like cells adhered to human cortical bone slices and produced resorption pits. These morphological and functional characteristics suggest that the cells we isolated and cultured were human osteoclasts and their precursors. Thus this method may provide a reliable means of obtaining human osteoclasts from normal tissue for short-term studies of their metabolism or from various skeletal diseases to study pathological aberrations and mechanisms.

Acid Phosphatase↗
PubMed1996

Variations in the inferior pelvic pathway of the lateral femoral cutaneous nerve: implications for laparoscopic hernia repair.

Laparoscopic repair of inguinal hernias is gaining acceptance in the repertoire of the general surgeon. However, nerve entrapment sequelae have been reported and appear to be higher with the laparoscopic approach. Contributing factors include pelvic variations in nerve pathways and the use of staples. We examined the pelvic relations of the lateral femoral cutaneous nerve (LFCN) to the anterior superior iliac spine (ASIS) and the iliopubic tract (IPT) because of the high morbidity of entrapment of this nerve, despite its low incidence. The LFCN, ASIS, and IPT were identified and their relationships measured in 48 male and 24 female cadavers ranging in age from 61 to 96 yr. The LFCN was located 1.7 (+/- 1.2) cm medial to the ASIS along the IPT and 1.4 (+/- 0.7) cm posterior (deep) to the IPT at this point, with no significant sex differences. The intrapelvic pathway of the LFCN, including its branches, varied widely so that in 18% of these specimens the LFCN was in either the vertical plane of the ASIS (13%) or in the plane of the IPT (5%). In 11% this nerve was within 1 cm of the ASIS. These data indicate that exclusive use of the ASIS as a guide for staple placement may result in entrapment of this nerve or its branches.

Aged↗
PubMed1996

Information technology, medical education, and anatomy for the twenty-first century.

Medicine is experiencing an escalating explosion of information. With more data available about more topics, the key questions are how to access and make sense of the medical information jungle. Skill in choosing and applying information is essential for both medical education and practice and will require new approaches to mastering data. Medical education, like medicine itself, will continue to be driven by technology, and we can expect our students to be increasingly computer literate. Thus the role of medical education will become more one of how to use this information than of obtaining the information itself. What medical education must focus on is the processing of information for appropriate medical care. This, in turn, depends upon practitioners having contexts in which the relevance and significance of information can be evaluated. New imaging technologies and molecular advances demand a broader understanding of both health and disease. With the information explosion "on line," how can a student use this to understand the structure and function of the human body in four dimensions? Anatomy, the structural basis for life, provides a unique and necessary perspective on the human body from the molecular to the macroscopic. A solid foundation in anatomy is the best preparation for an effective physical examination and for safe, efficient basic clinical procedures. Finally, anatomy laboratories provide a context for learning other important aspects of medicine-group process, clinical problem solving, and a sensitivity to human mortality. Advocating for these unique features of our discipline in medical education is the task facing anatomists as we end this millennium. The challenges and opportunities for us have never been greater, if we don't throw out the baby with the bath water.

Anatomy↗
PubMed1996

Outcome of pyriform sinus cancer: a retrospective institutional review.

Pyriform sinus cancer remains one of the most lethal of human diseases. Regardless of approach attempted significant enhancement of survival has not been realized. In this study a retrospective single institutional review of all patients diagnosed with pyriform sinus cancer during the 1980s was conducted. The results in 93 patients show an overall determinant 5-year survival of 14.3%. Of patients undergoing surgery, median determinant survival was 37 months and 5-year survival was 34.6%. In resectable patients treated with radiation with or without chemotherapy, median determinant survival was 13 months with 5-year survival of 7.1% (P < .01). Surgical salvage was attempted in 8 patients without success. In conclusion, due to the apparent survival advantage for surgical patients, the low rate of surgical salvage, and the relatively low rate of organ preservation in prospective trials, pyriform sinus cancer is a poor site for organ preservation. Surgery followed by radiation therapy should remain the standard of care for pyriform sinus cancer.

Aged↗
PubMed1996

Rib fractures in 31 abused infants: postmortem radiologic-histopathologic study.

PURPOSE: To examine the morphologic alterations of fractures of the lateral and anterior rib arcs and costochondral junction (CCJ) to better understand the factors that influence radiographic visualization and to gain insight into the mechanism of injury in rib fractures of abused infants. MATERIALS AND METHODS: Thirty-one infants (average age, 3 months) who died with inflicted skeletal injuries were studied with high-detail, pre- or postmortem skeletal surveys, or both, and radiography of specimens, with histologic analysis. The distribution and number of fractures were determined for each technique, and dating was performed on the basis of radiographic and histologic criteria. The radiologic features were correlated with the pathologic findings in comparable histologic sections. RESULTS: Of 165 fractures, 84 (51%) involved the ribs. Only 30 rib fractures (36%) were visible with skeletal survey examination. Lateral and anterior arc fractures tended to impact along the inner cortex of the rib. CCJ fractures tended to involve the inner aspect of the osteochondral interface with an associated osseous fragment. CONCLUSION: Acute and healing rib fractures are common in infants who died with inflicted injury; detection is technique-dependent. Use of high-detail skeletal radiography to identify these injuries in live and deceased infants appears justified.

Autopsy↗