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H L Gordon

Publications and source records attributed to H L Gordon.

16 recordsLinked to original sources
PubMed1992

Structural elements of human parathyroid hormone and their possible relation to biological activities.

Human parathyroid hormone (hPTH) and several deletion analogues were examined for the presence of secondary structure using circular dichroism spectroscopy. The spectra of hPTH and the deletion analogues 8-84, 34-53, 53-84, 1-34, 13-34, 1-19, and 20-34, in neutral, aqueous buffer, gave no evidence for extensive secondary structure. An alpha-helical-like spectral contribution was found to arise from a region within peptide 13-34. This spectral contribution was speculated to arise from partial stability of a helix consisting of residues 17-29. Molecular dynamics simulations of peptide 1-34 suggested that this peptide tends to fold with a bend defined by residues 10-14, with the amino-terminal and carboxyl-terminal residues tending to be in more extended forms and the other residues in helical-like conformations. The addition of trifluoroethanol promoted the formation of alpha-helix, mainly in the 1-34 region. The putative helix comprised of residues 17-29 was stabilized by the addition of 10-20% TFE, while a second putative helix proximal to the amino terminus, and comprised of residues 3-11, was stabilized by slightly higher concentrations of TFE. An amphiphilic sequence was identified within the 20-34 fragment. The development of alpha-helix on binding this fragment, and other analogues containing this sequence, to palmitoyloleoylphosphatidylserine vesicles provided experimental evidence for the potential role of this amphiphilic sequence in binding to membranes or to a membrane receptor. The relationships between these alpha-helical regions in 1-34, either potentiated by trifluoroethanol or lipid vesicles, are discussed in terms of different receptor-binding regions within hPTH.

Amino Acid Sequence↗
PubMed1992

Fuzzy cluster analysis of molecular dynamics trajectories.

We propose fuzzy clustering as a method to analyze molecular dynamics (MD) trajectories, especially of proteins and polypeptides. A fuzzy cluster analysis locates classes of similar three-dimensional conformations explored during a molecular dynamics simulation. The method can be readily applied to results from both equilibrium and nonequilibrium simulations, with clustering on either global or local structural parameters. The potential of this technique is illustrated by results from fuzzy cluster analyses of trajectories from MD simulations of various fragments of human parathyroid hormone (PTH). For large molecules, it is more efficient to analyze the clustering of root-mean-square distances between conformations comprising the trajectory. We found that the results of the clustering analysis were unambiguous, in terms of the optimal number of clusters of conformations, for the majority of the trajectories examined. The conformation closest to the cluster center can be chosen as being representative of the class of structures making up the cluster, and can be further analyzed, for example, in terms of its secondary structure. The CPU time used by the cluster analysis was negligible compared to the MD simulation time.

Amino Acid Sequence↗
PubMed1992

The relationship of the superficial and deep facial fascias: relevance to rhytidectomy and aging.

Controversy persists regarding the relationship of the superficial facial fascia (SMAS) to the mimetic muscles, deep facial fascia, and underlying facial nerve branches. Using fresh cadaver dissection, and supplemented by several hundred intraoperative dissections, we studied facial soft-tissue anatomy. The facial soft-tissue architecture can be described as being arranged in a series of concentric layers: skin, subcutaneous fat, superficial fascia, mimetic muscle, deep facial fascia (parotidomasseteric fascia), and the plane containing the facial nerve, parotid duct, and buccal fat pad. The anatomic relationships existing within the facial soft-tissue layers are (1) the superficial facial fascia invests the superficially situated mimetic muscles (platysma, orbicularis oculi, and zygomaticus major and minor); (2) the deep facial fascia represents a continuation of the deep cervical fascia cephalad into the face, the importance of which lies in the fact that the facial nerve branches within the cheek lie deep to this deep fascial layer; and (3) two types of relationships exist between the superficial and deep facial fascias: In some regions of the face, these fascial planes are separated by an areolar plane, and in other regions of the face, the superficial and deep fascia are intimately adherent to one another through a series of dense fibrous attachments. The layers of the facial soft tissue are supported in normal anatomic position by a series of retaining ligaments that run from deep, fixed facial structures to the overlying dermis. Two types of retaining ligaments are noted as defined by their origin, either from bone or from other fixed structures within the face.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1989

Chemical peel: a change in the routine.

The use of occlusive taping following phenol chemical peel has become a standard technique. Many studies have demonstrated the effectiveness of tape occlusion in producing a deeper, more profound chemical peel. For the last 18 months, we have abandoned tape occlusion following phenol peel and have substituted an occlusive dressing using a thick layer of petroleum jelly (Vaseline). The occlusiveness provided by the petroleum jelly has proved to be almost as effective as the standard tape mask, and the results using this technique parallel those with a tape mask. The advantages of Vaseline occlusive dressing include greater patient comfort, the ability to evaluate the wound beneath the petroleum jelly, and the prevention of streaking, which can occur from uneven tape application. Eschar formation and crust separation are avoided after the peel by the constant use of facial lubricants, our preference being A & D ointment.

Chemexfoliation↗
PubMed1989

Facemask hazard.

Explore the source record for details and available documents.

Equipment Failure↗
PubMed1988

Midazolam (Versed) in ambulatory surgery.

Midazolam is a very useful drug in outpatient aesthetic surgery. Its principal advantages are (1) short duration of action (a half-life of 2.3 hours), (2) painless injection, (3) no incidence of postoperative phlebitis (as compared with diazepam), and (4) a high degree of safety and effectiveness. Since one of the main objectives in outpatient surgery is to have the patient recover as quickly as possible and be discharged without any significant drug hangover, we recommend the incorporation of midazolam into the armamentarium of the aesthetic surgeon. Subsequent to the presentation of this paper (Twentieth Annual Meeting of the American Society for Aesthetic Plastic Surgery, in Los Angeles, California, March 23, 1987), we have administered midazolam to an additional 400 patients undergoing outpatient surgery and no apnea has occurred requiring an airway or supportive respiratory measures.

Ambulatory Surgical Procedures↗
PubMed1987

Operations postponed by anaesthetists: a prospective study.

A prospective study was carried out in one District Health Authority over a twelve month period to investigate the principal reasons for the postponement of operations on the advice of anaesthetic staff. A mean of 1.4% of all cases listed for general anaesthesia were postponed. The clinical indications for this are described and possible methods for reducing this figure are discussed.

Anesthesiology↗
PubMed1979

Chemical peeling as a practical method for removing rhytides of the upper lip.

Chemical peeling is a safe, effective method for removing upper lip lines, or rhytides, over a long period of time. While the predictable, undesirable sequela of loss of pigmentation occurs in a significant number of patients, the effectiveness and safety of the procedure seem to outweigh this problem. Chemical peeling has become an accepted and effective tool for eliminating upper lip lines due to aging, and should be considered by physicians undertaking treatment of the wrinkled upper lip.

Chemexfoliation↗
PubMed1978

Rhytidectomy.

The success of rhytidectomy depends on the selection of the patient, the technique and skill of the surgeon, and preparation of the patient prior to surgery. The patient must be made aware of what to expect before, during, and after the operation. Patients can expect to look presentable enough to appear in public in 2 to 3 weeks following the surgery. The final result will be apparent in from 6 to 8 weeks after surgery (Figs. 8-10).

Anesthesia, General↗
PubMed1977

Upper lid blepharoplasty.

We reviewed, retrospectively, our upper lid blepharoplasties to critically compare our own postoperative results after (1) conventional blepharoplasty, or (2) fixation of the levator aponeurosis to the lower margin of the orbicularis, or (3) fixation of the levator to the lower margins of the orbicularis and the skin. We found no demonstrable difference in our results with these 3 techniques. It is our opinion that the standard conventional blepharoplasty (including excision of a strip of orbicularis muscle) is preferable for use in most caucasian eyelids. The results are as good, it is simple, and it is less likely to cause problems.

Eyelids↗
PubMed1977

Rhytidectomy: a statistical analysis.

A statistical analysis of 1,500 consecutive rhytidectomies is presented. In rhytidectomy, complications occur in a significant percentage of the operations. The plastic surgeon must be aware of the incidence and significance of these complications, and also he must know how to avoid or manage them.

Age Factors↗
PubMed1977

Serum immunoglobulin levels in vasectomized men: preliminary report.

Seventy-five men undergoing vasectomy were tested by radial immunodiffusion assay prevasectomy and at 6 weeks and 3, 6, and 12 months postvasectomy for possible changes in serum immunoglobulin (Ig) levels. No significant changes occurred when the results were analyzed on a group basis per time period. However, when each individual's prevasectomy Ig level was considered as his norm, significant changes appeared to occur in serum IgG levels at 6 weeks, 6 months, and 12 months postvasectomy; in serum IgM levels at 6 weeks; but not, to date, in serum IgA levels. Seasonal, environmental, and infectious factors do not seem to be associated with the changes found. No significant seminal Ig changes have been demonstrated. Consideration of these findings and implications for possible immunopathology are briefly discussed.

Adult↗