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Biomedical subjects

S A Wolfe

Publications and source records attributed to S A Wolfe.

At least 19 recordsLinked to original sources
PubMed1992

Tissue-specific binding of testis nuclear proteins to a sequence element within the promoter of the testis-specific histone H1t gene.

The rat histone H1t gene is transcribed only in testis germinal cells. This testis-specific chromosomal protein is first synthesized during spermatogenesis in pachytene spermatocytes and the entire complement of testis histones is replaced during the midspermatid stage of spermiogenesis by positively charged transition nuclear proteins TP1 and TP2. Mobility shift assays conducted using crude nuclear protein extracts from different tissues and an 18-bp DNA sequence element within the H1t promoter as a probe reveal binding only with nuclear proteins from testis. The binding is specifically competed with an excess of the same unlabeled DNA fragment but not with heterologous competitors. A larger oligonucleotide corresponding to the same sequence element plus 18 bp of the adjacent downstream H1/CCAAT element binds nuclear proteins from all tissues tested, but a unique low mobility band is formed only with testis extracts. Protein-DNA crosslinking experiments reveal that two major polypeptides with molecular weights of approximately 13 and 30 kDa bind to the 18-bp H1t promoter sequence element. This strong correlation between the tissue where the H1t gene is transcribed and the presence of testis-specific nuclear proteins that bind to a sequence element within the testis histone H1t promoter supports the possibility that these DNA-binding proteins may participate in formation of an active transcription initiation complex with the testis H1t promoter.

Animals↗
PubMed1992

Temporal correlation between the appearance of testis-specific DNA-binding proteins and the onset of transcription of the testis-specific histone H1t gene.

The histone H1t gene is transcribed only in testis. Northern blot analyses reveal that transcription of the H1t gene occurs first in pachytene primary spermatocytes. Thus, there is a temporal correlation between onset of transcription of the gene and synthesis of histone H1t in primary spermatocytes during spermatogenesis. Previous studies revealed that replacement of most H1t and core histones occurs during the midspermatid stage of spermiogenesis by transition proteins TP1 and TP2. In this paper we extend our study of the specific binding of testis nuclear proteins to a unique sequence element within the H1t promoter. The relatively tight binding is competed with an excess of homologous DNA but not with a mutated element. Testis proteins from prepubertal animals do not bind to the 18-bp promoter element out proteins from enriched populations of primary spermatocytes do bind. Therefore, the temporal correlation between onset of transcription of the H1t gene and the time when the specific H1t promoter-binding proteins are detected in primary spermatocytes suggests that the DNA-binding proteins might be germinal cell-specific transcription factors that participate in formation of an active H1t transcription initiation complex. These studies present the first analysis of binding sites for testis nuclear proteins from primary spermatocytes within the promoter of a gene expressed only during this stage of spermatogenesis.

Animals↗
PubMed1991

Protein-DNA interactions within the rat histone H4t promoter.

The histone H4t gene is actively transcribed in rat testis germinal cells and in several non-testis cell types including cells from liver. This histone H4 gene is expressed most actively in testis premeiotic pachytene spermatocytes, and its expression is down-regulated in postmeiotic early spermatids. The histone H4 gene promoter is functional as demonstrated by finding significant levels of chloramphenicol acetyltransferase (CAT) mRNA in mammalian cells transiently transfected with a histone H4-promoted CAT expression vector compared to cells transfected with an expression vector lacking of the promoter. Examination of the proximal promoter of the histone H4 gene by electrophoretic mobility shift assays indicates that specific protein-DNA interactions occur when pachytene spermatocyte nuclear proteins are mixed with promoter fragments containing regions designated site I and site II, consensus sequence elements essential for regulating transcription of the histone H4 gene. These specific protein-DNA interactions are eliminated by competition with identical DNA fragments, but are not eliminated by competition with nonhomologous DNA fragments. Significant differences are found in mobility shift patterns upon comparison of nuclear proteins from germinal cell populations enriched in pachytene spermatocytes where the gene is actively expressed and early spermatids where the gene is not expressed.

Amino Acid Sequence↗
PubMed1991

Treatment of the particularly fatty neck and the short-interval secondary facelift.

In patients with normal body weight but with large accumulations of submental and cervical fat, good results can be obtained by an extensive subcutaneous dissection, carefully sculpted removal of the excess fat, and relatively limited work on the platysema. For some patients there may be an indication for a secondary facelift involving skin dissection alone within a relatively short interval.

Adipose Tissue↗
PubMed1991

Conservative treatment of genu valgus and varum with medial/lateral heel wedges.

Symptomatic bowlegs and knock-knees are common in the aging person and aging athlete secondary to knee trauma. Diagnosis is made by observation and in mild degrees by a standing alignment x-ray that shows narrowing of the joint surface on the appropriate side. The patients complained of pain on the convexity side of the deformity. Treatment consisted of a simple exercise program, non-steroidal anti-inflammatory drugs and appropriate 1/8-inch wedges on the lateral side of the heel for bowlegs or on the medial side of the heel for knock-knees. The effect of a simple heel wedge formed the basis for conservative treatment of symptomatic knee deformities.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1991

Malar augmentation using autogenous materials.

A variety of methods are available for malar augmentation using autogenous material, and the choice of procedure will depend on the indications presented by each particular case. The ability to produce a smooth natural contour without the need for concern of late problems is a decided advantage to the use of autogenous tissue. We have presented a compendium of available methods, demonstrated clinical examples and described a new technique, which, because of its simplicity, will certainly find further applications. A new method developed by Paul Tessier for malar augmentation is also described.

Humans↗
PubMed1990

Structural and functional analysis of the rat testis-specific histone H1t gene.

A 6.86 kb rat genomic DNA fragment containing the testis-specific histone H1t gene and the histone H4t gene has been sequenced. S1-nuclease protection analyses of total cellular RNA from rat liver and testis showed that histone H1t mRNA was present only in testis. Examination of various highly enriched populations of rat testis cell types revealed that H1t mRNA was found exclusively in a fraction enriched in pachytene spermatocytes. When protein, DNA interactions within the proximal promoter region of the histone H1t gene were examined by electrophoretic mobility shift assays, only minor differences were found in mobility shift patterns of the H1t promoter in assays comparing binding of nuclear proteins from pachytene spermatocytes and early spermatids. However, major differences in binding were observed upon comparing nuclear proteins from rat pachytene spermatocytes to liver. Comparison of binding patterns of rat testis, rat hepatoma H4 cells, HeLa cells, and COS-1 cells also revealed dramatic differences. Transcriptional activity of the histone H1t promoter was examined by measuring H1t promoted chloramphenicol acetyltransferase (CAT) mRNA levels in transient expression assays in transfected rat hepatoma H4 cells, HeLa cells, and COS-1 cells. These assays revealed that the histone H1t promoted CAT gene functioned poorly in HeLa cells and COS-1 cells compared to expression with the parent SV40 promoted vector pSV2CAT. The H1t promoted CAT gene apparently did not work at all in transfected rat hepatoma H4 cells, which is consistent with testis germinal cell specific expression of the histone H1t gene.

Animals↗
PubMed1990

Modifications of protein-DNA interactions in the proximal promoter of a cell-growth-regulated histone gene during onset and progression of osteoblast differentiation.

A temporal sequence of interrelated cellular, biochemical, and molecular events which occurs during the progressive expression of the differentiated osteoblast phenotype in primary cultures of fetal rat calvarial cells results in the development of a bone-tissue-like organization. This ordered developmental sequence encompasses three periods: proliferation, matrix maturation, and mineralization. Initially, the cells actively proliferate and synthesize type I collagen. This is followed by a period of matrix organization and maturation and then by a period of extracellular matrix mineralization. At the completion of proliferation, when expression of osteoblast phenotype markers such as alkaline phosphatase is observed, the cell-cycle-related histone genes are down-regulated transcriptionally, suggesting that a key signaling mechanism at this transition point involves modifications of protein-DNA interactions in the regulatory elements of these growth-regulated genes. Our results demonstrate that there is a selective loss of interaction of the promoter binding factor HiNF-D with the site II region of an H4 histone gene proximal promoter that regulates the specificity and level of transcription only when the down-regulation of proliferation is accompanied by modifications in the extracellular matrix that contribute to progression of osteoblast differentiation. Thus, this specific loss of protein-DNA interaction serves as a marker for a key transition point in the osteoblast developmental sequence, where the down-regulation of proliferation is functionally coupled to the appearance of osteoblast phenotypic properties associated with the organization and maturation of an extracellular matrix that becomes competent to mineralize.

Animals↗
PubMed1990

The anatomy and clinical applications of the buccal fat pad.

The buccal fat pad is an anatomically complex structure that has great importance in facial contour. In properly selected individuals, judicious harvesting of buccal fat can produce dramatic changes in facial appearance by reducing the fullness of the cheek and highlighting the malar eminences. Using fresh cadaver dissection, the anatomy of the buccal fat pad is delineated and its relationship to the masticatory space, facial nerve, and parotid duct is defined. An intraoral approach for buccal fat harvesting is described based on these anatomic findings. Clinical experience manipulating the buccal fat pad for aesthetic modification of facial contour is illustrated.

Adipose Tissue↗
PubMed1990

The postauricular way-station for tubed pedicles from the chest.

A method is described for staging the transfer of a tube pedicle from the chest to the head by means of a preliminary attachment to the postauricular region. The advantages of this method are that it increases the range of the pedicle, provides a delay or at least a proof of the vascularity of the distal portion of the flap at the same time as the inset, and prevents downward gravitational pull on the pedicle and limitation of the patient's cervical motion, which have been difficulties with chest pedicles in the past.

Adult↗
PubMed1990

Corticotropin-releasing factor receptors in mouse spleen: identification of receptor-bearing cells as resident macrophages.

CRF is a primary integrator of the organism's coordinated neuroendocrine, autonomic, behavioral, and immune responses to stress. In the present study the identity of the cell type(s) expressing CRF receptors in mouse spleen was determined using a combination of cell fractionation and receptor-binding techniques. Autoradiographic studies of the distribution of [125I]Tyro-ovine CRF [( 125I]oCRF)-binding sites in spleen localized CRF receptors primarily to the red pulp and marginal zones. The distribution pattern of [125I]oCRF-binding sites closely resembled the pattern of India ink accumulated in phagocytic cells in the same sections. To identify the specific cell type(s) expressing CRF receptors, [125I]oCRF-binding activity was evaluated in splenic cell populations fractionated on the basis of their physical and functional properties. Macrophages were identified in each fraction by their phagocytosis of polystyrene beads and membrane labeling with MONTS-4, a monoclonal antibody specific for resident macrophages. Spleen cells were fractionated by adherence to glass bead or Sephadex G-10 columns, phagocytosis of carbonyl iron particles, and centrifugation on discontinuous Percoll gradients. By all fractionation methods, there was a significant correlation of [125I]oCRF binding with both phagocytic activity (r = 0.75; P less than 0.001) and MONTS-4 staining (r = 0.84; P less than 0.001), strongly suggesting that CRF receptors are primarily expressed on resident splenic macrophages. However, there was essentially no specific binding of [125I]oCRF to either resident or elicited peritoneal macrophages or to several monocyte/macrophage, B-cell, or T-cell lines. While these results suggest that the expression of CRF receptors may be restricted to a population of splenic macrophages, they do not exclude the possibility that CRF receptors may be induced on resident macrophages in spleen and other immune system-related tissues by factors present in the microenvironment.

Animals↗