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Biomedical subjects

W D Johnson

Publications and source records attributed to W D Johnson.

At least 127 records · Page 7Linked to original sources
PubMed1989

Pruritic skin lesions. A common initial presentation of acquired immunodeficiency syndrome.

During July 1983 to December 1984, we observed that 62 (46%) of 134 Haitian patients with acquired immunodeficiency syndrome had intensely pruritic eruptions for which neither specific causative nor categoric diagnoses could be established. These lesions were a presenting manifestation of acquired immunodeficiency syndrome in 79% of the patients and appeared a mean of 8 months before the diagnosis of either Kaposi's sarcoma or opportunistic infection. Lesions included erythematous round macules, papules, or nodules that first appeared on the extensor surface of the arms, but subsequently involved the legs, trunk, and face. Histologically, the lesions were characterized by varying degrees of mixed (predominantly eosinophilic) perivascular and perifollicular inflammatory cell infiltrates of the dermis. The lesions did not respond to any therapeutic regimens used and usually persisted throughout the acquired immunodeficiency syndrome illness. Demographic and laboratory data did not distinguish these patients from those without pruritic skin lesions.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Factors influencing long-term (10-year to 15-year) survival after a successful coronary artery bypass operation.

The long-term survival of 6,181 consecutive patients who underwent a coronary bypass operation from 1972 to 1986 was evaluated in relation to certain risk factors: age at the time of operation, sex, preoperative left ventricular function, presence of diffuse coronary artery disease, and previous coronary bypass operation. Advanced age markedly reduced the 10-year and 15-year survival. When compared with the general population, however, the survival of patients in the older age groups (over 60 years) exceeded that of the general population at 10 and 15 years. In patients under 55 years of age, the 10-year and 15-year survival is less than that of the general population. Male and female patients of comparable ages had virtually identical 10-year and 15-year survival rates. Severe left ventricular dysfunction, previous coronary bypass operation, and diffuse coronary artery disease requiring coronary artery endarterectomy all adversely affected the long-term survival rates. Within all age groups studied there was a significant benefit in survival with either one or more mammary artery bypass grafts. The data presented provide an important historical control group that can be used in evaluating the long-term results after successful coronary bypass operations.

Adult↗
PubMed1989

Relationship between oedema, blood pressure, and blood flow following local brain injury.

Vasogenic brain oedema is a concomitant of a wide variety of central nervous system lesions that have in common a disturbance of the blood-brain barrier permeability. Although it is well established that the formation and spread of this extracellular type of oedema is influenced directly by variations of systemic arterial pressure, the consequences of these events on local cerebral blood flow are not known. In the current experiments, vasogenic brain oedema was produced in rats by cold-injury lesions, and local cerebral blood flow measurements were made using a technique of 14C-antipyrine quantitative autoradiography under pharmacologically controlled conditions of hypertension, hypotension, and normotension. Evidence is presented that the formation and spread of vasogenic brain oedema is accompanied by the development of a congruent zone of decreased local cerebral blood flow, and that the magnitude of this field of oedema/ischaemia is a direct function of systemic arterial pressure. These findings may have important clinical implications.

Animals↗
PubMed1989

Antigen-specific immunosuppression in visceral leishmaniasis is cell mediated.

Visceral leishmaniasis is associated with an antigen-specific immunosuppression during the acute disease. Patients become responsive to Leishmania antigen in both in vivo and in vitro assays after successful antimony therapy. The cell type involved in the suppression of lymphocyte reactivity to Leishmania antigen was studied by selective depletion of mononuclear cell (MNC) populations and in co-cultivation experiments. Adherent cells were depleted on plastic and by passage on nylon wool columns. High-avidity Fc+ cells were depleted by adherence to BSA-anti-BSA complexes and OKT4+ and OKT8+ cells were depleted by treatment with monoclonal antibody (anti-OKT4+ and OKT8+) and complement. Depletion of MNC preparations of adherent cells, high-avidity Fc+ cells, OKT4+ cells and OKT8+ cells failed to restore the lymphocyte reactivity to Leishmania antigen. Antimony therapy was associated with restoration of the proliferative responses of unseparated MNC (before treatment 460 +/- 76 cpm and after treatment 4,293 +/- 1,442 cpm). Co-culture of frozen cells obtained before chemotherapy with autologous MNC obtained after treatment reduced the response of posttreatment cells to Leishmania antigen by 80%. We conclude that the antigenic specific suppression of lymphocyte proliferation in visceral leishmaniasis is cell mediated.

Adolescent↗
PubMed1989

AIDS in Haiti.

The first cases of AIDS in Haiti were recognized in 1978-1979, a period that coincides with the earliest reports of AIDS in the United States. Current data are consistent with the hypothesis that AIDS originated in Africa, came to the United States and Europe, and subsequently was introduced into Haiti by either tourists or returning Haitians. The seroprevalence of HIV among healthy sexually active adults in Port-au-Prince, Haiti, is approximately 10%. This rate of HIV infection is threefold that observed in rural areas. The highest prevalence rates were observed in female prostitutes (53%) and in the male and female spouses of AIDS patients (55%). The types of opportunistic infections and the clinical course in Haitians with AIDS were similar in many respects to those in patients with AIDS in the United States. Important differences were noted in the prevalence of specific opportunistic pathogens in Haiti. It resembled observations on these infections in Africa. During the past 4 years, there has been a progressive decrease in the percent of patients reporting bisexuality and blood transfusions, and an increase in those reporting either a spouse with antecedent AIDS, prostitution, or none of the aforementioned activities. In 1986, heterosexual transmission probably accounted for over 70% of AIDS cases.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Percutaneous transluminal coronary angioplasty: a surgeon's perspective.

Percutaneous transluminal coronary angioplasty is a valuable adjunct in the treatment of various groups of patients with symptomatic coronary artery disease. In the authors' opinion, it is most valuable in patients with single-vessel disease of the right, circumflex, or distal left anterior descending coronary arteries. We also have found PTCA to be extremely helpful in managing patients with very complex coronary anatomy in whom surgery has not been completely successful or is not a reasonable option. Patients with triple-vessel disease or proximal left anterior descending lesions are treated best surgically. The value of many recent advances in PTCA techniques and long-term results (over 10 years), as well as the results of randomized studies, should help to clarify the situations in which PTCA and coronary bypass surgery are complementary, and those in which they are competitive.

Angioplasty, Balloon, Coronary↗
PubMed1988

Percutaneous transluminal coronary angioplasty in patients with two or more previous coronary artery bypass grafting operations.

Between 1979 and 1986, 65 of 76 patients (86%) (82% men, with a mean age of 58 +/- 8 years) with greater than or equal to 2 previous coronary artery bypass grafting (CABG) operations and symptomatic myocardial ischemia underwent successful percutaneous transluminal coronary angioplasty (PTCA). Sixty-two patients had 2 prior CABG operations, 10 had 3 and 4 had 4. Clinical characteristics included prior myocardial infarctions in 49 (65%), severe angina (class III or IV) in 47 (62%) and left ventricular ejection fraction less than or equal to 35% in 13 (17%). There were 139 lesions dilated: 1 lesion in 39 (51%), 2 in 22 (29%) and greater than or equal to 3 in 15 (20%) patients. Arterial lesions were successfully dilated in 71 of 81 cases (88%), vein grafts in 44 of 53 (83%) and mammary artery grafts in 3 of 5 (60%). In 12 patients, PTCA was used to dilate significant lesions less than 15 days after CABG in vessels which were unable to be bypassed. Significant complications were encountered in 4 patients (5%). These included 3 of 53 vein graft dilatations with embolization (6%), with 1 resulting in infarction and death, and 1 patient dying after emergency CABG. At hospital discharge, 65 patients were clinically improved. An apparent symptom-related lesion recurrence occurred in 23 of 65 patients (35%), with 5 patients dying of cardiac causes, 4 having CABG without previous angiography and 12 of 14 patients undergoing repeat successful PTCA (mean time and standard deviation 9 +/- 6 months).(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1988

Triple vessel coronary artery endarterectomy and reconstruction: results in 144 patients.

Coronary artery endarterectomy and reconstruction are valuable adjuncts to conventional bypass surgery when attempting to revascularize "diffusely" diseased coronary arteries. One hundred forty-four consecutive patients were operated on through February 1986, all of whom required endarterectomy and reconstruction of the left anterior descending, left circumflex and right coronary arteries. There were 130 men (90%), ranging in age from 29 to 83 years (average 55.8), whose left ventricular ejection fraction ranged from 0.20 to 0.75 (average 0.54). One hundred thirty-one patients (91%) had angina preoperatively, which was Canadian Cardiovascular Society class III or IV in 85 (59%). Fifteen operations (10%) were repeat procedures. All operations were performed using intermittent ischemic arrest. There was an average of 5.0 grafts per patient (range 3 to 8), with an average of 3.8 endarterectomized vessels per patient (range 3 to 7). There were 14 surgical deaths (10%), all cardiac in origin. Statistically significant (p less than 0.01) risk factors for increased operative mortality included repeat surgery, ejection fraction less than or equal to 0.30 and age greater than or equal to 70 years. The operative mortality rate in 106 low risk patients (male gender, age less than 70 years, ejection fraction greater than 0.30, first operation) was 3.8% (4 patients). Nonfatal complications included 13 perioperative myocardial infarctions (10%). Long-term follow-up data are available for all 102 surviving patients for an average of 30 months (range 7 to 92). There were 12 late deaths 1 to 52 months postoperatively. The 5 year actuarial survival rate is 71% for the entire group and 87% for the 106 low risk patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Peripheral neuropathy associated with dietary riboflavin deficiency in the chicken. I. Light microscopic study.

Chickens fed a riboflavin-deficient diet from hatching had leg weakness and paralysis as early as 12 days of age. Signs worsened through day 16; after 35 days, recovery was evident. Sciatic nerves from affected chickens were enlarged. Significant microscopic lesions were confined to peripheral nerves and included tissue separation (suggesting interstitial edema), Schwann cell swelling, perivascular leukocytic infiltration, and segmental demyelination accompanied by accumulation of osmiophilic debris in Schwann cell cytoplasm. Axon degeneration was present, but was not a primary lesion. Acid phosphatase enzyme activity of Schwann cells was increased in affected nerves. These results demonstrate that dietary riboflavin deficiency causes a demyelinating peripheral neuropathy in young, rapidly growing chickens.

Animals↗
PubMed1988

Results of coronary artery endarterectomy and reconstruction.

Since 1978, 5005 patients have had coronary artery bypass operations: 50% had conventional grafts only (group A), 25.1% required one coronary artery endarterectomy (group B), and 24.9% required multiple endarterectomies (group C). Operative mortality and long-term survival were stratified within each group according to the presence of additional risk factors: severe left ventricular dysfunction, repeat operation, insulin-dependent diabetes mellitus, female sex, and age over 70 years. Operative mortality was 4.0% in group A patients, 6.3% in group B, and 10.4% in group C; it increased in each group as the number of risk factors increased. Mortality was higher in patients with a left coronary artery endarterectomy compared to those with a right coronary endarterectomy only when multiple risk factors were present. Perioperative myocardial infarction occurred in 5.6% of group A patients, 6.5% of group B, and 13.1% of group C patients. Early graft patency (940 patients, 18.8%) was 801 of 901 (88.9%) for endarterectomy grafts and 2939 of 3248 (90.5%) for conventional grafts. Late patency (over 1 year) in 288 symptomatic patients was 137 of 191 (71.1%) for endarterectomy grafts and 644 of 850 (75.8%) for conventional vein grafts. Long-term (5-year) actuarial survival rate was reduced in patients requiring endarterectomy. Current anginal status is available for 3011 of 3305 patients (91.1%): 28.9% of group A patients, 32.5% of group B, and 33.7% of group C patients have recurrent angina at an average follow-up of 58.3 months. The results of this study show increased operative mortality and morbidity in patients requiring coronary artery endarterectomy and reconstruction. However, the early results and particularly the late survival, clinical status, and continued graft patency justify this approach in patients with diffuse coronary artery disease, many of whom would otherwise be inoperable.

Adult↗
PubMed1988

Coronary artery bypass grafting for the third time or more. Results of 150 consecutive cases.

Through December 1986, coronary artery bypass surgery was performed on 150 patients who had undergone at least two previous myocardial revascularization surgeries. One hundred thirty-seven patients had two, 12 patients had three, and one patient had four previous operations. There were 117 men (78.0%); the mean age was 55.5 years (range, 28-76 years); 137 patients (91.3%) had triple-vessel disease, and 36 (24.0%) had a left ventricular ejection fraction less than 0.40. One hundred forty-nine patients (99.3%) had angina preoperatively, with 142 (94.7%) having Class III and IV angina. Direct myocardial revascularization was performed in all patients, with a mean of 3.3 grafts per patient (range, 1-6). In addition, coronary artery endarterectomy was performed in 70 cases (46.7%): right coronary artery endarterectomy in 15 (10.0%), left coronary artery endarterectomy in 39 (26.0%), and multiple coronary artery endarterectomies in 16 (10.7%). There were 18 in-hospital deaths (12.0%). Statistically significant risk factors for increased early mortality (p less than 0.01) included age over 65 years and left ventricular ejection fraction less than 0.40. Diffuse coronary artery disease requiring multiple coronary artery endarterectomies almost achieved statistical significance as a risk factor (p = 0.06). Complications in the surviving 132 patients included seven nonfatal perioperative myocardial infarctions (5.3%). Follow-up data for a period of 8-172 months (mean, 43.1 months) is available for 100 of 103 patients (97.1%). Five-year actuarial survival was 76.4% for the entire series and 87.3% for hospital survivors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Treatment of candida esophagitis in AIDS patients.

We conducted a randomized prospective study to compare the efficacy of oral miconazole and ketoconazole in the treatment of candida esophagitis in acquired immune deficiency syndrome (AIDS) patients in Haiti. Twelve AIDS patients with endoscopic and microscopic diagnoses of candida esophagitis were placed on either oral miconazole or ketoconazole for 10 days. All six patients receiving oral miconazole, and four of the six receiving ketoconazole had complete resolution of their esophageal lesions at the end of treatment. We conclude oral miconazole is at least as effective as ketoconazole in the treatment of candida esophagitis in AIDS patients.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Clinical evaluation of a commercial photorefractor.

The Visiscreen 100 is a system designed to detect ocular anomalies photographically. Photorefractions obtained in 63 consecutive 3-month-old to 8-year-old patients were compared in a masked fashion with results obtained by conventional techniques, including cycloplegic refraction. In 87% of the 57 patients with analyzable photographs, photorefractive and examination results correlated for the detection of constant tropias. The photorefractor detected all ocular media opacities. In 77% of the cases, its refraction was within 2.5 diopters or 33% of the cycloplegic spherical equivalent. In detecting abnormal ocular status, the Visiscreen had a 91% sensitivity and a 74% specificity. The overall agreement rate in distinguishing abnormal from normal status was 84%. Most errors were related to inaccuracies in fixation and positioning, rather than the optical principles utilized. This device offers a rapid technique for the detection of factors predisposing preverbal children to amblyopia.

Child↗
PubMed1987

Cross reactivity between Trypanosoma cruzi and Leishmania antigens in the lymphocyte blastogenesis assay.

The in vitro blastogenesis response of lymphocytes from 19 patients, with either visceral or mucocutaneous leishmaniasis or Chagas disease, to antigens of the Leishmania-Trypanosoma complex was studied. Cells from all patients responded to both homologous and heterologous antigens and the magnitude of the responses did not differ for any of the patient groups or antigens.

Adolescent↗
PubMed1987

Epidemiology of American cutaneous leishmaniasis due to Leishmania braziliensis braziliensis.

A five-year prospective study of cutaneous leishmaniasis in an endemic area of Brazil revealed an annual incidence of disease of 8.1 per 1000 inhabitants and a prevalence of 14.9%. The disease fluctuated as a series of mini-epidemics. Most disease occurred in individuals who were 10-30 years of age. Mucosal disease occurred in 2.7% of patients with primary lesions and occurred a median of six years after this lesion. Disease was more common in males, in those with either large or multiple antecedent skin lesions, and in those with incomplete antimony therapy for the primary lesions. An ELISA was positive in 85% of those tested during the first two years after the primary lesion and remained positive for five to 40 years in 27% of patients. Skin testing was positive in 96% of patients with recent lesions and remained positive in 70% of patients. All patients with mucosal disease had positive serological and skin tests.

Adolescent↗