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Biomedical subjects

M Wolff

Publications and source records attributed to M Wolff.

At least 217 records · Page 12Linked to original sources
PubMed1993

Effects of chemotherapeutic and immunosuppressive drugs on the production of erythropoietin in human hepatoma cultures.

The effects of agents used in combination chemotherapy were studied on erythropoietin synthesis in cultures of the human hepatoma cell line, HepG2. Erythropoietin was measured by radioimmunoassay in the culture media after 24-h treatment periods. The RNA synthesis-inhibiting drugs daunorubicin, cyclophosphamide, ifosfamide, and cis-diamine-dichloroplatinum produced a dose-dependent decrease of the production of erythropoietin. Inhibition was also induced by the tubulin-binding agents vincristine and colchicine and the immunosuppressive agents azathioprine and cyclosporin A. The DNA synthesis-inhibiting drugs methotrexate and cytosine arabinoside, the antimycotics 5-fluorocytosine and amphotericin B, and glucocorticoids did not inhibit. Viability studies showed that the inhibition of erythropoietin production was partly correlated with cytotoxicity. These data could be relevant with respect to recombinant erythropoietin replacement therapy in tumor-associated anemia.

Animals↗
PubMed1993

Vaccination with Haemophilus influenzae type b meningococcal protein conjugate vaccine reduces oropharyngeal carriage of Haemophilus influenzae type b among American Indian children.

The effect of Haemophilus influenzae type b (Hib) meningococcal protein conjugate vaccine (Hib-OMPC; Merck, Sharp & Dohme) on oropharyngeal (OP) carriage of Hib was evaluated in Navajo and Apache Indian children, who are known to be at high risk for invasive Hib disease. We obtained 1423 OP swabs at well child visits from 1321 children 3 months to 4 years of age: 293 of the swabs were obtained from children before the administration of any Hib-OMPC; 1119 were taken after the primary vaccination series; and 11 after the booster dose. Swabs were tested for the presence of Hib capsular polysaccharide antigen by enzyme-linked immunosorbent assay. Forty of 1423 swabs were positive for Hib. Among the 40 positive swabs 5 (13%) were obtained from children who had received Hib-OMPC vaccine appropriate for age at swabbing, compared with 500 of 1383 (36%) of negative swabs. Children who were OP carriers of Hib were older than noncarriers (mean age, 13 and 9 months, respectively) and a greater proportion of carriers (48%) had symptoms of respiratory infection at the time of swabbing than noncarriers (30%). These variables were significantly related to increased risk of OP carriage of Hib when incorporated jointly in a logistic regression model: not vaccinated according to age (odds ratio 2.7, 95% confidence interval 1.00 to 7.05); increase of age in months (odds ratio 1.1, 95% confidence interval 1.02-1.10); and respiratory infection symptoms present (odds ratio 2.0, 95% confidence interval 1.06-3.77). Thus besides preventing invasive Hib disease, appropriate vaccination with Hib-OMPC appears to reduce OP carriage of Hib.

Bacterial Outer Membrane Proteins↗
PubMed1993

Microelectrode measurements of pericellular PO2 in erythropoietin-producing human hepatoma cell cultures.

On the basis of Fick's law of gas diffusion, it has been proposed that cells in conventional monolayer cultures may be severely hypoxic. Because knowledge of the cellular O2 availability is important for the interpretation of biochemical and toxicological cell culture work, microelectrode measurements of the pericellular PO2 were carried out using the erythropoietin (Epo)-producing human hepatoma cell lines Hep G2 and Hep 3B as an in vitro model. In confluent hepatoma cultures grown in polystyrene dishes and incubated in air with 5% CO2, the pericellular steady-state PO2 was < 1 mmHg. The rates of the production of immunoreactive Epo and lactate were high due to a misproportion between O2 supply and O2 requirements. Epo production decreased when shaken instead of static cultures were studied, or when the O2 concentration in the gas atmosphere was increased gradually up to 95%. In cultures grown on gas-permeable supports, pericellular and gas PO2 values were very similar, with increased Epo production at lowered PO2. In agreement with mathematical models, our experimental data make PO2 measurements desirable for studies of O2-dependent biological functions in cell cultures.

Carcinoma, Hepatocellular↗
PubMed1993

Medical hypothesis: xenoestrogens as preventable causes of breast cancer.

Changes in documented risk factors for breast cancer and rates of screening cannot completely explain recent increases in incidence or mortality. Established risk factors for breast cancer, including genetics, account for at best 30% of cases. Most of these risk factors can be linked to total lifetime exposure to bioavailable estrogens. Experimental evidence reveals that compounds such as some chlorinated organics, polycyclic aromatic hydrocarbons (PAHs), triazine herbicides, and pharmaceuticals affect estrogen production and metabolism and thus function as xenoestrogens. Many of these xenoestrogenic compounds also experimentally induce mammary carcinogenesis. Recent epidemiologic studies have found that breast fat and serum lipids of women with breast cancer contain significantly elevated levels of some chlorinated organics compared with noncancer controls. As the proportion of inherited breast cancer in the population is small, most breast cancers are due to acquired mutations. Thus, the induction of breast cancer in the majority of cases stems from interactions between host factors, including genetics and environmental carcinogens. We hypothesize that substances such as xenoestrogens increase the risk of breast cancer by mechanisms which include interaction with breast-cancer susceptibility genes. A series of major epidemiologic studies need to be developed to evaluate this hypothesis, including studies of estrogen metabolism, the role of specific xenoestrogenic substances in breast cancer, and relevant genetic-environmental interactions. In addition, experimental studies are needed to evaluate biologic markers of suspect xenoestrogens and biologic markers of host susceptibility and identify pathways of estrogenicity that affect the development of breast cancer. If xenoestrogens do play a role in breast cancer, reductions in exposure will provide an opportunity for primary prevention of this growing disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Neoplasms↗
PubMed1993

Septic shock due to toxoplasmosis in patients infected with the human immunodeficiency virus.

PURPOSE: To describe the presentation and clinical course of septic shock due to Toxoplasma gondii in patients infected with the human immunodeficiency virus (HIV). PATIENTS AND METHODS: From April 1988 to February 1992, nine HIV-infected patients were admitted because of predominant septic shock (7 patients) or developed septic shock in the ICU (2 patients). The recent CD4+ cell count ranged from 2 to 84 x 10(6)/L. RESULTS: The main clinical features were (1) a history of fever for longer than 15 days, with a recent increase to more than 39.5 degrees C; (2) a recent history of dyspnea (< 15 days, 8 cases; < 7 days, 3 cases); and (3) recent onset of thrombocytopenia (6 of 9 cases). All patients were in shock (hyperkinetic profile in 6 of 7; hypokinetic in 1 of 7), and 8 of 9 were in respiratory distress (ratio of PaO2 over fractional concentration of oxygen in the inspired gas of 117 +/- 23; range, 88 to 155). Chest roentgenograms revealed diffuse alveolar infiltrates in six of nine cases. The serum lactate dehydrogenase (LDH) activity was 6,510 +/- 5,080 IU/L (range, 1,010 to 15,450 IU/L). Serologic tests for T gondii were negative in two cases. Toxoplasma gondii was isolated from lung (9/9), bone marrow (5/7), or blood (2/2). One, 3, and 2 patients had brain, ocular, and myocardial involvement, respectively. No other microbial pathogens were isolated. Seven patients died, 5 less than 3 days after admission. CONCLUSION: Disseminated toxoplasmosis can cause septic shock in HIV-infected patients. In two cases, the disease was probably a primary infection. The association of high fever, acute dyspnea, recent onset of thrombocytopenia, and a very high level of LDH activity is suggestive of disseminated toxoplasmosis.

AIDS-Related Opportunistic Infections↗
PubMed1993

Transdermal nicotine substitution: pharmacokinetics of nicotine and cotinine.

The use of tobacco has resulted in major health related problems worldwide. Nicotine replacement is one of the most promising strategies in smoking cessation. The in vivo delivery rate and the pharmacokinetic properties of a recently developed transdermal nicotine system (TNS) was investigated in three separate studies. Two sizes (16 cm2 and 24 cm2) of the patches were tested. Mean daily nicotine delivery, expressed by a first order kinetic, varied between 0.9 and 1.0 mg/cm2 patch. The different sizes of the patches led to linearly dose-related nicotine plasma Cmax- and AUC-values. The nicotine levels achieved were in the same range with those of other nicotine patches and the chewing gum. As a result of multiple dose kinetic, no significant accumulation of nicotine was observed. Mean elimination half-life of nicotine after removal of the patches (3.5 +/- 1.8 h for the larger patch and 4.5 +/- 1.9 h for the smaller patch) was longer than reported values after i.v. administration, which was reported to vary between 40 and 120 min.

Administration, Cutaneous↗
PubMed1993

[BCGitis as a cause of mediastinal tumor].

In a one year old female infant BCG-vaccinated as a neonate, a large mediastinal mass was found after routine examination. X-ray and CT scan suggested a teratoma. Histology and microbiology, however, revealed the diagnosis of an active tuberculosis. Thus, the tumor was caused by mediastinal BCGitis. To our knowledge this complication of BCG-vaccination has not yet been described.

BCG Vaccine↗
PubMed1993

Four years' experience with triple procedures in herpes-afflicted eyes.

Keratoplasties are performed relatively frequently in herpes-afflicted eyes. However, intraocular lenses (IOLs), for eyes with intraocular recurrent herpes simplex virus (HSV) disease remain a verdict in most surgical centers. As most herpetic disease is uniocular and cataract is a frequent complication in the long run, a real need exists for triple procedures in such eyes so as to achieve their full visual rehabilitation. Taking full advantage of systemic aciclovir therapy and prophylaxis, we started with triple procedures in herpes-afflicted eyes in 1987. Up to July 1991, we operated on 29 eyes, and 28 could be optically rehabilitated. One eye was given up and received a conjunctival cover for sociomedical reasons. Three repeat keratoplasties (10%) were necessary, and a considerable number of complications had to be overcome; ten eyes suffered from sustained fibrinous exsudations (35%), ten were threatened by one or more endothelial immune therapy reactions (35%), and ten experienced one or more herpes recurrences (35%), mostly intraocular recurrences. As this study was not performed as a randomized, placebo-controlled, double-blind study, no absolute scientific proof of aciclovir's value in these patients can be presented. Nonetheless, we would conclude from the exceedingly good rehabilitation rate of 96% observed during an average follow-up period of 19 months that in all probability, systemic aciclovir was in the first rank responsible for this success rate. Thus, there is good clinical evidence that systemic aciclovir prophylaxis and therapy is indeed the most important key for successful triple procedures in eyes afflicted with herpetic disease.

Acyclovir↗
PubMed1992

Crystallization and preliminary X-ray analysis of human endothelin.

Endothelin, a potent regulator of vasoconstriction and hypertension, is a naturally produced peptide of 21 amino acids containing two disulfide bonds. We have crystallized endothelin from humans using the vapor-diffusion technique, characterized the crystals by X-ray diffraction analysis, and have collected the X-ray intensities to a resolution of 1.8 A. The crystals, which demonstrate physical properties similar to most protein crystals and have a comparable solvent content, are hexagonal prisms that frequently grow to lengths of 400 microns and widths of 150 microns. The space group of the crystals is P6(1)22 (or P6(5)22), with a = 27.4, c = 79.6 A. There is one molecule of endothelin in the asymmetric unit of the crystals.

Crystallization↗
PubMed1992

A controlled trial in intensive care units of selective decontamination of the digestive tract with nonabsorbable antibiotics. The French Study Group on Selective Decontamination of the Digestive Tract.

BACKGROUND: Selective decontamination of the digestive tract with topical nonabsorbable antibiotics has been reported to prevent nosocomial infections in patients receiving mechanical ventilation, and the procedure is used widely in Europe. However, it is unclear whether selective decontamination improves survival. METHODS: We conducted a randomized, double-blind multicenter study in which 445 patients receiving mechanical ventilation in 15 intensive care units were given either prophylactic nonabsorbable antibiotics (n = 220) or a placebo (n = 225). Topical antibiotics (tobramycin, colistin sulfate, and amphotericin B) or a placebo was administered through a nasogastric tube and applied to the oropharynx throughout the period of ventilation. The main end points were the mortality rate in the intensive care unit and within 60 days of randomization. RESULTS: A total of 142 patients died in the intensive care unit; 75 (34 percent) in the treatment group and 67 (30 percent) in the placebo group (P = 0.37). Mortality within 60 days of randomization was similar in the two groups (P = 0.40), even after adjustment for factors that were either unbalanced or individually predictive of survival in the two groups (P = 0.70). Pneumonia developed in 59 patients (13 percent) in the intensive care unit within 30 days of enrollment in the study (33 in the placebo group and 26 in the treatment group, P = 0.42). Pneumonia acquired in the intensive care unit and due to gram-negative bacilli was less frequent (P = 0.01) in the treatment group than in the placebo group. The total charges for antibiotics were 2.2 times higher in the treatment group. CONCLUSIONS: Selective decontamination of the digestive tract does not improve survival among patients receiving mechanical ventilation in the intensive care unit, although it substantially increases the cost of their care.

Administration, Topical↗
PubMed1992

Skeletal muscle toxoplasmosis in patients with acquired immunodeficiency syndrome: a clinical and pathological study.

The present article describes the clinical and pathological findings in 5 human immunodeficiency virus (HIV)-infected patients with muscle toxoplasmosis. The patients had marked lymphopenia (5/5), with less than five CD4+ cells/mm3 (3/3), when they developed fever (5/5), and multiorgan failure (5/5), including diffuse encephalitis, pneumonia, pancytopenia, and myopathy. Muscle involvement included weakness and wasting (4/5), myalgias (3/5), and high serum creatine kinase levels (3/3). Serology for toxoplasmosis showed high IgG titers in 3 patients (3/4). Anti-Toxoplasma therapy resulted in complete recovery in 2 patients. Muscle toxoplasmosis was detected by biopsy (3/5) or postmortem evaluation (2/5), and was identified using immunocytochemistry and electron microscopy. Toxoplasma cysts were detected in 0.5 to 4% of muscle fibers close to or remote from necrotic fibers and inflammatory infiltrates. Muscle fibers strongly expressed the major histocompatibility complex class I antigen (2/2) as in polymyositis. We suggest that Toxoplasma gondii should be sought by muscle biopsy in patients who have acquired immunodeficiency syndrome with fever, encephalitis, multiorgan dysfunction, and elevated serum creatine kinase levels of obscure origin.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Continuous positive airway pressure by face mask or mechanical ventilation in patients with human immunodeficiency virus infection and severe Pneumocystis carinii pneumonia.

We reviewed the records of 44 patients with AIDS who had 45 episodes of severe Pneumocystis carinii pneumonia (PCP). While 9 patients required intubation and mechanical ventilation (MV) on admission, continuous positive airway pressure (CPAP) by face mask was the initial measure in 36 episodes. There were 25 patients managed with CPAP alone, 23 of whom survived. Among the reasons for delayed intubation and MV (11 patients) was that treatment failure was strongly associated with non-survival, since all 6 such patients died. The in-hospital mortality for severe PCP in this study was 33% overall, and reached 65% for mechanically ventilated patients. The 1-year survival was 43% (95% confidence interval, 28%-58%). These data confirm the improved prognosis for patients with AIDS and severe PCP, and suggest that mask CPAP may be an adequate mean of ventilatory support in this setting.

Adult↗
PubMed1992

Monokines inhibiting erythropoietin production in human hepatoma cultures and in isolated perfused rat kidneys.

The blood level of erythropoietin (Epo) is often anomalously low in anemic patients with inflammatory or malignant diseases. Therefore, we studied effects of pure recombinant immunomodulatory peptides on Epo formation in cultures of the human hepatoma cell line, HepG2. Interleukin (IL)-1 beta, IL-1 alpha, and tumor necrosis factor alpha lowered Epo production with half-maximal inhibition at 2, 5, and 20 U/ml, respectively. IL-6, transforming growth factor beta 2 and interferon gamma did not inhibit. Furthermore, IL-1 beta (10 U/ml) proved to block Epo formation in isolated serum-free perfused rat kidneys. Proposedly, monokines play a role in the pathogenesis of Epo deficiency in various diseases.

Animals↗
PubMed1992

Pain relief using cutaneous modalities, positioning, and movement.

Positioning, movement, and certain cutaneous modalities may be easily used by all caregivers, including the family, to bring comfort and pain relief to terminally ill patients with pain. For such patients, these techniques are most appropriately used in addition to pharmacologic control of pain. Patients themselves may use some of the cutaneous modalities with minimal assistance from others, thereby promoting a sense of independence. Other techniques may be performed by family and friends, providing them with the assurance that they are assisting a loved one. The techniques presented here can be readily used in the home or hospital setting and are relatively low risk, simple, and inexpensive. This paper presents specific guidelines for patients and caregivers in relation to the use of superficial massage, superficial heat and cold, menthol application to skin, transcutaneous electrical nerve stimulation (TENS), positioning, and movement. Because of their simplicity and ease of use, these techniques tend to be overlooked. However, taking the time to introduce these techniques to patients and families often results in a significant contribution to the comfort of the dying patient.

Cryotherapy↗
PubMed1992

Evaluation of bacterial polysaccharide immune globulin for the treatment or prevention of Haemophilus influenzae type b and pneumococcal disease.

A human hyperimmune globulin termed bacterial polysaccharide immune globulin (BPIG) has been prepared from plasma donors immunized with Haemophilus influenzae type b (Hib), pneumococcal, and meningococcal vaccines. At a dose of 0.5 ml/kg, BPIG increased levels of antibody to Hib by greater than 0.15 microgram/ml within 4-6 h and by 2-4 micrograms/ml at 72 h. Thereafter, antibody declined, with a mean half-life of 27 days. BPIG treatment of Apache infants did not impair their active antibody responses to concurrently administered diphtheria-tetanus-pertussis or Hib oligosaccharide-diptheria CRM197 conjugate vaccines. In high-risk Apache infants, BPIG given at 2, 6, and 10 months of age provided significant protection from invasive Hib infection during infancy. Thus, BPIG may have utility in the prevention of Hib infections in high-risk patients who cannot be immunized adequately with Hib conjugate vaccines.

Antibodies, Bacterial↗
PubMed1992

Prevention of Haemophilus influenzae type b infections in Apache and Navajo children.

Prospective surveillance of Haemophilus influenzae type b (Hib) disease has been done since 1981 in two high-risk populations, White Mountain Apaches and Navajos. The attack rate in children less than 5 years of age is 5-10 times higher than in the general US population. Three vaccines were evaluated. Unconjugated Hib capsular polysaccharide produced lower antibody responses in 18- and 24-month-old Apache infants than in white infants. HbOC (Hib oligosaccharide covalently linked to the nontoxic mutant diphtheria toxin CRM197) produced low antibody responses in Navajo infants after one or two doses but induced responses similar to those in whites after three doses. The responses of 18-month-old Navajos to HbOC were lower than those of whites, but most achieved protective levels. PRP-OMP (Hib capsular polysaccharide linked to the outer membrane protein complex of Neisseria meningitidis) produced good immune responses in 2-month-old Navajo and Apache infants after a single dose. This vaccine was greater than 90% efficacious in protecting Navajo infants from Hib disease when given at 2 and 4 months of age. Even a single dose achieved a high protective efficacy.

Antibodies, Bacterial↗