Search PubMed⌕ Search

Biomedical subjects

A Parker

Publications and source records attributed to A Parker.

At least 163 records · Page 9Linked to original sources
PubMed1973

Clinical experience with the Dalkon Shield intrauterine device.

Preliminary acceptability and reliability tests of the Dalkon Shield were done in 377 women over 17 months, amounting to 3,028 months of use. There was a 98% follow-up. The pregnancy rate of 4.7 and expulsion rate of 6.3 do not meet the claims described in initial trials by the developers of the device. Nevertheless, the Dalkon Shield seems to be an advance in intrauterine contraception since it has the advantages of a lower expulsion rate than the "first generation" inert intrauterine devices.

Adult↗
PubMedDate not supplied

Autologous collagen dispersion (Autologen) as a dermal filler: clinical observations and histologic findings.

OBJECTIVE: To assess the histologic behavior and clinical efficacy of autologous collagen dispersion (Autologen) in augmenting human dermis. SUBJECTS: Adult patients of the Facial Plastic Surgery Clinic at The New York Eye and Ear Infirmary who were undergoing facial aesthetic surgery with skin excision. METHODS: Five patients were injected intradermally with Autologen in one postauricular area and bovine cross-linked collagen (Zyplast) on the contralateral side. Patients were examined clinically for signs of infection, skin necrosis, or implant rejection/allergy 2, 4, and 12 weeks postinjection. Impressions and photographs of all implant sites were taken at all follow-up visits. Biopsy specimens of each implant were taken 4 and 12 weeks after injection and examined histologically for signs of integration, rejection, and resorption. RESULTS: All implants were well tolerated. No identifiable differences were noted in the clinical persistence of Zyplast vs Autologen. Histologically, there was more variability in the degree of fibroblast infiltration of Autologen vs Zyplast deposits. CONCLUSIONS: Our trial suggests that autologous collagen dispersion may represent a viable alternative to bovine collagen. Clinical persistence and histologic behavior of Autologen appear to be at least as favorable as those of Zyplast, and Autologen obviates the need for allergy testing and eliminates the possibility of disease transmission. Arch Facial Plast Surg. 2000;2:48-52

Adult↗
PubMedDate not supplied

Evaluation of acellular dermal graft in sheet (AlloDerm) and injectable (micronized AlloDerm) forms for soft tissue augmentation. Clinical observations and histological analysis.

OBJECTIVES: To evaluate the histological and clinical properties of (1) subdermally implanted acellular dermal graft (AlloDerm) sheets vs intradermal bovine collagen and (2) subdermally or intradermally injected micronized AlloDerm vs type I bovine collagen cross-linked with glutaraldehyde (Zyplast). PATIENTS: Twenty-five adult patients testing nonallergic to bovine collagen. METHODS: (1) Stacked disks of AlloDerm were implanted subdermally behind one ear, and bovine collagen was injected intradermally behind the other. The soft tissue augmentation caused by the implants was measured by digital photography at 1, 4, and 12 weeks, and biopsy specimens of each implant type were examined at 3 months after implantation. (2) Micronized AlloDerm was injected intradermally and subdermally in 2 different locations behind one ear, and bovine collagen was injected in the same manner behind the other. The soft tissue augmentation caused by the implants was measured by digital photography at the time of implantation and at 1 and 4 weeks after implantation. All implants were examined 1 month after implantation. RESULTS: All patients tolerated both implants well. (1) AlloDerm implants retained a higher percentage of the original implant volume than Zyplast at 1 and 3 months after implantation. Histologically, AlloDerm implants were extensively invaded by host fibroblasts without any foreign body reaction. (2) Intradermally injected micronized AlloDerm implants retained a higher percentage of the original implant volume at 1 month after implantation than intradermal Zyplast. Histologically, micronized AlloDerm implants were extensively invaded by host fibroblasts without any foreign body reaction. No significant differences were noted between subdermally injected micronized AlloDerm and Zyplast. CONCLUSIONS: The macroscopic and microscopic behavior of subdermally implanted AlloDerm sheets and subdermally and intradermally injected micronized AlloDerm was compared with intradermally injected Zyplast. AlloDerm sheet volume persisted to a significantly (P < .001) greater degree than bovine collagen during the first 3 months after placement. Clinically, intradermally injected micronized AlloDerm volume persisted to a significantly (P = .01, .04, and .01, respectively) greater degree than intradermal Zyplast or subdermal micronized AlloDerm or Zyplast. Histologically, micronized AlloDerm and AlloDerm are well tolerated at 1 and 3 months, respectively. Host tissue incorporation with fibroblast in-growth and collagen deposition is seen in both materials. AlloDerm and micronized AlloDerm hold promise for use in facial soft tissue augmentation.

Adult↗
PubMedDate not supplied

Evaluation of acellular dermal graft (AlloDerm) sheet for soft tissue augmentation: a 1-year follow-up of clinical observations and histological findings.

OBJECTIVES: To evaluate and compare the long-term clinical persistence and histological appearance of subdermally implanted acellular dermal graft (AlloDerm) sheets and intradermal type I bovine collagen cross-linked with glutaraldehyde (Zyplast). PATIENTS: Ten adult patients (5 men and 5 women; average age, 46 years; age range, 37-59 years) not allergic to bovine collagen. METHODS: AlloDerm sheets were implanted surgically in a subdermal plane in one postauricular crease, and Zyplast was injected intradermally on the opposite side. AlloDerm and Zyplast implants were digitally photographed and their apparent volumes calculated at 1, 3, 6, 9, and 12 months after implantation. A specimen was removed at 3 and 12 months and examined histologically for collagen persistence, host tissue invasion, and inflammatory reaction. RESULTS: The apparent implant volume of the AlloDerm sheets decreased during the first 6 months and then stabilized over the next 6 months. By contrast, Zyplast was progressively absorbed, with complete loss of clinical effect by 6 months. Histological analysis of implanted AlloDerm sheets demonstrated progressive repopulation of the graft with minimal inflammation. CONCLUSIONS: AlloDerm sheets seem to provide stable soft tissue augmentation after an early period of resorption and are clearly superior to Zyplast injections for long-term, large-volume, soft tissue correction. Recommendations for clinical use include routine overcorrection, with subsequent augmentation delayed by at least 6 months.

Adult↗
PubMedDate not supplied

The DNA sequence and comparative analysis of human chromosome 20.

The finished sequence of human chromosome 20 comprises 59,187,298 base pairs (bp) and represents 99.4% of the euchromatic DNA. A single contig of 26 megabases (Mb) spans the entire short arm, and five contigs separated by gaps totalling 320 kb span the long arm of this metacentric chromosome. An additional 234,339 bp of sequence has been determined within the pericentromeric region of the long arm. We annotated 727 genes and 168 pseudogenes in the sequence. About 64% of these genes have a 5' and a 3' untranslated region and a complete open reading frame. Comparative analysis of the sequence of chromosome 20 to whole-genome shotgun-sequence data of two other vertebrates, the mouse Mus musculus and the puffer fish Tetraodon nigroviridis, provides an independent measure of the efficiency of gene annotation, and indicates that this analysis may account for more than 95% of all coding exons and almost all genes.

Animals↗
PubMedDate not supplied

Burn excision with intraoperative vasopressin.

Reducing blood flow to the skin during burn wound excision should decrease blood loss, which remains a major problem during primary excision of large burns. This clinical investigation demonstrates that arginine-vasopressin appears to reduce intraoperative blood loss and is relatively free of complications. This treatment has potential benefits for the patient with small burns as well. The amount of banked blood required could be greatly reduced, thus decreasing the risks of transfusion and the cost of burn care.

Adult↗