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Biomedical subjects

R Reid

Publications and source records attributed to R Reid.

At least 163 records · Page 9Linked to original sources

Physical and surgical principles governing carbon dioxide laser surgery on the skin.

Although the physical principles governing the safe delivery of coherent radiation are well established, these rules are broken as often as they are followed. Few surgeons take advantage of the increased precision afforded by the rapid superpulse mode. Through a misdirected sense of caution, many surgeons use dangerously low power outputs and choose power densities in the carbonization range. Surface ablation is often undertaken with a beam geometry suited only to thermal incision, thereby producing an array of ridges and gutters that must be flattened by a raster technique. Each sequential pass of the laser adds to the amount of unnecessary thermal injury. Finally, some surgeons still try to control the laser in delicate situations through turning down beam power rather than through the strategy of prolonging reaction time with gated pulses. Of course, simple observation of correct physical principles does not guarantee a successful outcome. Strategies are also required to ensure dextrous beam delivery and to minimize thermal injury within adjacent tissue. As in other forms of surgery, the dermatologic surgeon must learn how to control bleeding, gain exposure, delineate geographic margins, and control the depth of destruction. When these lessons are assimilated, wounds heal rapidly, and results are indistinguishable from normal tissue.

Carbon Dioxide↗

Physical and surgical principles of laser surgery in the lower genital tract.

This article discusses the correct physical principles and strategies necessary to produce successful results with the CO2 laser. When the correct techniques are applied, CO2 laser treatment of HPV-associated disease within the male or female genital tract carries a primary success rate of 85% to 95%. Unless correct techniques are applied, laser surgery carries a risk of unintended thermal injury.

Biophysical Phenomena↗

CO2 laser for suppurative hidradenitis of the vulva.

Chronic suppurative hidradenitis is a disease of the apocrine glands occurring predominantly in the axillae of the anogenital region. Treatment, to date, has been frustrating. Prolonged antibiotic therapy and multiple incisions and drainage have been the usual form of therapy, but those surgical procedures leave patients with ugly scars; retracted, hypertrophic skin edges; and pitted, indurated and disfiguring abscesses. The only successful treatment to date has been wide excision of the entire apocrine gland-bearing tissues, such as radical vulvectomy, which often necessitates grafts to cover the surgically exposed areas. That has left patients with unsatisfactorily functioning vaginas and a mutilated appearance. Recently we instituted the use of the CO2 laser to treat these patients with the goal of eradicating the suppurative sinus tracts and the infected apocrine glands without removing large volumes of adjacent, unaffected tissue. Over the past eight years we treated 11 patients who had extensive, chronic hidradenitis of the anogenital area with the CO2 laser. The use of laser therapy for these patients has produced effective and less-mutilating results. Such treatment has been a successful option for treating this debilitating disease.

Adult↗

A double-blind, randomized trial of 0.5% podofilox and placebo for the treatment of genital warts in women.

Patient-applied formulations of 0.5% podofilox (podophyllotoxin) were evaluated for the treatment of external genital warts in a double-blind, placebo-controlled study. Seventy-two women were enrolled and, using a randomized, computer-generated list, assigned to receive either active drug or placebo in a 2:1 ratio. Patients were instructed to apply the medication to their external warts twice each day for 3 consecutive days, followed by 4 days without treatment. This cycle was repeated at weekly intervals for a maximum of 4 weeks (and a minimum of 2 weeks). Patients were evaluated weekly for the first month and then at weeks 6 and 10. The number of warts present was recorded and the overall improvement was assessed. The treated area was examined, the patients were questioned about any adverse effects, and standard hematologic/biochemical studies were conducted. The final results showed that podofilox cleared 74% of the total wart count, compared with an 18% regression in the placebo group (P less than .001). The investigators' assessments of improvement correctly distinguished active drug from placebo at every observation point. Local untoward effects were minor and transient. There was no evidence of systemic effects. It is concluded that patient-applied podofilox is a safe and effective therapy for genital condylomata in women. When available, this drug will simplify the treatment of genital warts by providing a patient-applied alternative therapy.

Adolescent↗

Role of a soy-based lactose-free formula in the outpatient management of diarrhea.

The introduction of a soy-based, lactose-free formula during the acute phase of diarrheal illness in infants has been shown to reduce stool output and duration of diarrhea in hospitalized patients. In the United States, most infants with acute diarrhea are treated as outpatients. In the present study, infants with diarrhea who were treated as outpatients were randomly assigned to receive either a soy-based, lactose-free formula alternating with oral rehydration solution from the beginning of therapy ("early feeding") or oral rehydration solution alone for the first 24 hours of therapy, followed by a soy-based, lactose-free formula alternating with oral rehydration solution (control group). Twenty-nine infants were randomly assigned to the early-feeding group and 27 to the control group. Twenty-one (72%) of 29 in the early-feeding group resolved their diarrhea at the end of 48 hours of therapy compared with 12 (44%) of 27 in the group fed oral rehydration solution only (P = .02). It is concluded that the introduction of a soy-based, lactose-free formula from the beginning of therapy for acute diarrhea in children treated as outpatients is safe and may shorten duration of diarrhea while maintaining adequate caloric intake.

Ambulatory Care↗

Rotavirus diarrhoea in Apache children: a case-control study.

A case-control study of rotavirus diarrhoea in Apache children up to two years old was conducted at the White Mountain Apache reservation from 1 May through 15 December 1985 to identify risk factors for rotavirus diarrhoea. The mothers of fifty cases, forty-five hospital controls and twenty-five neighbourhood controls participated in this study. Exposure to other children with diarrhoea stood out as the single most important factor for acquiring rotavirus diarrhoea (Odds ratio = 14.0). Other significant risk factors were living in homes with septic tanks and in homes with 'poor environmental sanitation.'. Minimizing contacts of children with diarrhoea therefore would be the most effective measure in preventing the spread of this disease in the community.

Arizona↗

Silent testicular metastasis from carcinoma of the prostate.

Secondary testicular tumours are rare, but metastasis of prostatic carcinoma to the testis is being reported more frequently. While this may not reflect a true increased incidence, more cases are detected by bilateral orchiectomy. Of 916 patients with carcinoma of the prostate diagnosed and treated over a period of 10 years, 124 underwent bilateral orchiectomy. Three patients were found to have testicular metastasis, 1 being bilateral. The route of spread seems to be through the lumen and/or lymphatics of the vas deferens. Although it is a sign of advanced disease, the prognostic significance is undetermined.

Aged↗

Screening for gynecologic cancer.

Screening principles, methods, and terminology are discussed for cervical, endometrial, and ovarian cancers. Incidence and mortality, risk factors, adjuncts to screening, and historic perspectives are also covered.

Adult↗

Superficial laser vulvectomy. IV. Extended laser vaporization and adjunctive 5-fluorouracil therapy of human papillomavirus-associated vulvar disease.

Although most human papillomavirus infections can be managed satisfactorily by office methods, extensive, refractory, and dysplastic vulvar disease poses frustrating problems. This observational cohort study evaluated the efficacy of extended laser ablation (vaporization of both clinically apparent and adjacent subclinical changes) among 160 women drawn from 1000 referrals between 1982-1987. During the final 2 years, the protocol incorporated two different 5-fluorouracil (5-FU) regimens: routine once-weekly applications as prophylaxis against postoperative recurrence, and twice-weekly dosing to avoid further laser surgery among patients with early but diffuse failures. One hundred seven patients (66.9%) were controlled by a single operation. Subsequent therapy for the remaining 53 women involved 44 additional superficial photovaporizations, 38 courses of therapeutic 5-FU, four deep laser destructions with skin grafting, and six trials of systemic alpha-interferon. Eventually, 158 patients (98.7%) entered stable clinical remission. Adjuvant 5-FU improved success rates among the 76 women with two or more adverse prognostic factors (87.5 versus 55.8%; P less than .01) but had no prophylactic value in the other 84 women. In contrast, the therapeutic 5-FU regimen was generally effective, avoiding the need for further surgery in 22 (57.9%) of 38 inevitable failures, compared with only four successes (10.3%) among 39 historic controls managed with caustic agents (chi 2 = 19.5; P less than .001). Improvements in laser technology had no impact upon outcome, but more sophisticated heat containment strategies reduced postoperative pain, healing time, and morbidity. Given adequate technique and an appropriate indication, we find extended laser ablation to be an excellent primary control method. However, the availability of an effective adjuvant regimen would be a valuable complement.

Cohort Studies↗

Passive immunization for infection with Haemophilus influenzae type b.

Haemophilus influenzae type b is the leading cause of meningitis in children younger than 5 years of age in the United States. The incidence of infection with H influenzae type b in certain populations, such as Apache and Navajo Indians and Alaskan Eskimos, is 10 to 20 times higher than in the general US population. Another important feature of H influenzae type b infections in these populations is that more than 80% of the cases occur during the first year of life, with 35% to 45% occurring during the first 6 months. One of the currently licensed vaccines that contains the capsular polysaccharide of the H influenzae type b organism is not reliably immunogenic in infants younger than 18 months of age. A number of new H influenzae type b vaccines prepared by covalently coupling the H influenzae type b capsular polysaccharide with a protein carrier antigen are undergoing clinical evaluation. One of these conjugate vaccines was shown to be efficacious in preventing disease caused by H influenzae type b in Finnish infants when they were immunized at 3, 4, and 6 months of age. Unfortunately, in a recently concluded trial, the same vaccine was not found to be efficacious in preventing such disease in infants younger than 1 year of age among the Alaskan Eskimo population. We have evaluated an alternative approach for protecting high-risk infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Bacterial↗

Infantile gastroenteritis associated with excretion of pestivirus antigens.

Faeces from children under 2 years old who had gastroenteritis that could not be attributed to recognised enteric pathogens were examined with a monoclonal-antibody-based immunoassay for Pestivirus antigens. Such antigens were detected in 30 of 128 episodes of gastroenteritis. Children without diarrhoeal disease and children infected with rotaviruses had little evidence of Pestivirus infection (faeces positive in 1 of 28 and 1 of 31, respectively). The diarrhoeal disease in children excreting Pestivirus antigens resembled that in other children except that it was more commonly associated with signs and symptoms of respiratory inflammation.

Antibodies, Monoclonal↗

Correlation of the histologic appearance of intraepithelial neoplasia of the cervix with human papillomavirus types. Emphasis on low grade lesions including so-called flat condyloma.

Cervical condylomas and intraepithelial neoplasia (CIN) were correlated with human papillomavirus (HPV) types and analyzed for the presence of abnormal mitotic figures. Colposcopically directed cervical biopsies were divided in half and processed for routine microscopy and Southern blot hybridization. Of 83 specimens from 71 patients, 70 (84%) contained HPV-DNA sequences. The HPV distribution was as follows: HPV 16 in 6/25 flat condylomas (FC), 2/8 CIN I, 8/18 CIN II, 12/14 CIN III; HPV 18 in 1/25 FC; HPV 31 in 3/25 FC, 3/18 CIN II, and 1/14 CIN III; HPV 6/11 in 12/18 exophytic condylomas (EC), 5/25 FC, 2/8 CIN I, and 3/18 CIN II. Uncharacterized HPVs were identified in 4/18 EC, 5/25 FC, 2/8 CIN I, and 1/18 CIN II. A similar heterogeneous distribution of HPV types was found in flat condylomas and CIN I. A more homogeneous distribution was noted in the exophytic condylomas and high grade CIN lesions, with HPV 6/11 found in the former and predominantly HPV 16 in the latter. Abnormal mitotic figures were predominantly seen in the high grade CIN lesions. Based on our findings, we would recommend that the term flat condyloma be abandoned and that low grade flat lesions of the cervix be graded according to CIN criteria.

Blotting, Southern↗

Hostile personality characteristics and prostaglandins in essential hypertension.

The hostile personality characteristic of dominance was shown to be significantly lower in a group of 34 male patients with essential hypertension than in a general illness control group (n = 17) in the USA. This replicates a previous finding from research in Greece into this and other conditions of presumably psychogenic origin. Nonspecific neurotic syndromes (as identified by the Present State Examination, a semistructured interview) were more prevalent in hypertensives than in controls, but no clear neurotic cases were found. Levels of the prostaglandins 6-keto prostaglandin F1A and thromboxane B2 did not differ significantly between groups, but the former was positively correlated with dominance in the control group. An interpretation of these results in terms of the repressed hostility theory is offered.

6-Ketoprostaglandin F1 alpha↗

Insertion and extension of acyclic, dideoxy, and ara nucleotides by herpesviridae, human alpha and human beta polymerases. A unique inhibition mechanism for 9-(1,3-dihydroxy-2-propoxymethyl)guanine triphosphate.

The ability of human alpha and beta DNA polymerases and herpes simplex virus type 2 (HSV-2) and human cytomegalovirus (HCMV) DNA polymerases to insert and extend several nucleotide analogs has been investigated using a variation of Sanger-Coulson DNA sequencing technology. The analogs included the triphosphates of two antiviral nucleosides with incomplete sugar rings: 9-(1,3-dihydroxy-2-propoxymethyl)guanine (dhpG) and 9-(2-hydroxyethoxymethyl)guanine (acyG or acyclovir), as well as dideoxy and arabinosyl nucleoside triphosphates. Three pairs of contrasting behaviors were found, each pair distinguishing the two human polymerases from the two viral ones: first, extension behavior with araNTPs; second, insertion/extension behavior with dhpGTP; and third, the relative preference for insertion of ddGTP versus acyGTP. The relative level of insertion of the nucleotide analogs by HCMV and HSV-2 DNA polymerases was dhpGTP greater than (acyGTP and araNTP) greater than ddGTP, whereas by human alpha polymerase it was araATP greater than ddGTP much greater than (acyGTP and dhpGTP) and by human beta polymerase it was (araATP and ddGTP) much greater than (acyGTP and dhpGTP). Evidence is presented for three mechanisms of inhibition by extendible nucleotides (of dhp and ara types) exhibiting frequent internalization: araATP acted as a simple pseudoterminator of alpha and beta polymerases, but was easily extended past singlet sites by Herpesviridae polymerases and only stalled at sites requiring two or more araATP insertions in a row. Herpesviridae polymerases stalled after adding dhpGMP and one additional nucleotide, suggesting that polymerase translocation problems may be a factor in polymerase inhibition by modified sugar nucleotide analogs. The amino acid sequence of the human alpha DNA polymerase, which is acyGTP resistant, was found to vary by one amino acid from the amino sequences of the Herpesviridae polymerases in a region of significant similarity and probable functional homology. Amino acid differences at that same site differentiate acyclovir-resistant HSV-1 mutants from the acyclovir-sensitive HSV-1 wild type.

Base Sequence↗