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Biomedical subjects

D Landers

Publications and source records attributed to D Landers.

18 recordsLinked to original sources
PubMed1997

Analysis of the maternal components of the AIDS clinical trial group 076 zidovudine regimen in the prevention of mother-to-infant transmission of human immunodeficiency virus type 1.

To gain insight into the protective effects of the three components of the zidovudine regimen used in AIDS Clinical Trial Group (ACTG) 076 on mother-to-infant transmission of human immunodeficiency virus (HIV) type 1, 188 zidovudine-treated women and their untreated infants from five HIV-1 obstetric centers were retrospectively studied. The overall rate of mother-to-infant transmission was 12.3% (95% confidence interval [CI], 7.9%-18.0%). When the 38 women with <200 CD4 cells/microL were excluded, the mother-to-infant transmission rate was 8.8% (95% CI, 4.6%-14.8%). This rate compares favorably with the 8.3% transmission in the zidovudine arm of the ACTG 076 study. Apart from low (<200/microL) maternal CD4 cells (P = .016), no factors, including the duration of zidovudine therapy during gestation and intravenous administration of zidovudine during labor, affected the rate of mother-to-infant transmission. These findings suggest that antenatal oral zidovudine may be as effective as antenatal oral plus intravenous zidovudine during labor and the three-component ACTG 076 regimen in decreasing mother-to-infant HIV-1 transmission.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Organochlorine contaminants in fish from an arctic lake in Alaska, USA.

A wide range of organochlorine pesticides and polychlorinated biphenyls (PCBs) were measured in muscle tissue and livers of lake trout (Salvelinus namaycush) and Arctic grayling (Thymallus arcticus) from Schrader Lake in Arctic Alaska. Results confirm the long-range transport of these contaminants to a US Arctic freshwater system. The most abundant group of compounds in all tissues was composed of PCBs. Mean concentrations of the sum of a selected group of PCB congeners ranged from 3.2 ng/g in grayling liver to 22.8 ng/g in trout liver and from 1.3 ng/g in grayling muscle to 6.6 ng/g in trout muscle (wet wt.). The second most abundant group was composed of chlordane-related compounds. No significant correlations of organochlorine concentrations with fish weight or length were observed for the data set as a whole. There were marked differences in sigma PCB, sigma chlordane and p,p'-DDE concentrations between species. The biomagnification factors for these compounds are similar to ratios reported for other aquatic systems. Comparisons showed that contaminant concentrations in lake trout from Schrader Lake were similar to levels found in burbot and slightly higher than levels in whitefish reported in Canadian studies from the Mackenzie River Delta.

Alaska↗
PubMed1995

Parturients infected with human immunodeficiency virus and regional anesthesia. Clinical and immunologic response.

BACKGROUND: It is estimated that 1.5 million Americans are infected with the human immunodeficiency virus (HIV-1), and the consequences of HIV infection are a leading cause of death in women aged 15-44 yr. Thus, HIV-1 disease, or acquired immunodeficiency syndrome, occurs with increasing frequency in the parturient, and there is little information concerning the risks of regional anesthesia. Fear of spreading infection to the central nervous system or adverse neurologic sequelae have led some clinicians to advise against regional anesthesia. Thus, this study was undertaken to evaluate the possible problems or risks associated with regional anesthesia in parturients infected with HIV-1 and to determine whether anesthesia affected the clinical course of the disease. METHODS: The clinical course and immunologic function of 30 parturients infected with HIV-1 were evaluated prospectively. Extensive medical and laboratory evaluation before delivery and 4-6 months postpartum was undertaken. Medical problems related to HIV-1 disease and use of antiviral drugs also were monitored. The anesthetic management was dictated by the clinical situation and the patient's wishes were careful postpartum follow-up to evaluate possible neurologic changes or infection. RESULTS: Regional anesthesia was administered in 18 parturients, and 12 received small doses of opioids or no analgesia. There were no changes in the immunologic parameters studied (CD4+, p24, beta 2 microglobulins), and HIV-1 disease remained stable in the peripartum period. There were no infections, complications, or neurologic changes in the peripartum period. Sixty-eight percent of the infants were HIV-1-negative and, in 21% of infants, the HIV-1 status was indeterminate (probably negative). CONCLUSIONS: This prospective study of parturients infected with HIV-1 demonstrated that regional anesthesia can be performed without adverse sequelae. There were no neurologic or infectious complications related to the obstetric or anesthetic course. The immune function of the parturient was stable in the peripartum period. Although the number of patients studied was small, with careful medical evaluation, regional anesthesia is an acceptable choice in the parturient infected with HIV-1.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Inhibition of calmodulin-dependent myosin light-chain kinase by growth-hormone-releasing factor and vasoactive intestinal peptide.

In view of the ability of calmodulin to bind vasoactive intestinal peptide (VIP) and growth-hormone-releasing factor (GRF) with high affinity [Stallwood, Brugger, Baggenstoss, Stemmer, Shiraga, Landers and Paul (1992) J. Biol. Chem. 267, 19617-19621], the effects of these neuropeptides on a model calmodulin-dependent enzyme, myosin light-chain kinase (MLCK), were studied. Both peptides were potent inhibitors of MLCK activity. The inhibition of enzyme activity by VIP and GRF was progressively overcome with increasing calmodulin concentrations, with no inhibition observed at a saturating calmodulin concentration. Nanomolar concentrations of MLCK blocked the formation of calmodulin-[125I-Tyr10]VIP complexes. These data provide support for a functional role of VIP and GRF binding by calmodulin.

Amino Acid Sequence↗
PubMed1994

Partitioning of vasoactive intestinal polypeptide into lipid bilayers.

Incubation of radiolabeled vasoactive intestinal polypeptide (VIP) with preformed lipid vesicles composed of phosphatidylcholine, phosphatidylglycerol and cholesterol resulted in reversible and saturable association of the peptide with the lipid bilayer. The pH-optimum for the reaction was in the physiological range. The vesicle-associated peptide displayed enhanced stability to proteolytic digestion, it was efficiently released into the supernatant by detergent-solubilization of the vesicles but remained vesicle-associated during treatment with agents that disrupt ionic interactions. Peptide binding by electrically neutral vesicles was lower than that by negative vesicles. Electron spin resonance studies with 5-doxylstearic acid or 16-doxylstearic acid labeled vesicles suggested that VIP decreased the fluidity close to the surface of the bilayer and increased the fluidity in its hydrophobic core. These observations suggest that VIP can bind and penetrate lipid bilayers.

Amino Acid Sequence↗
PubMed1994

Association between anti-human immunodeficiency virus type 1 (HIV-1) antibody-dependent cellular cytotoxicity antibody titers at birth and vertical transmission of HIV-1.

Because vertical transmission of human immunodeficiency virus type 1 (HIV-1) from mother to infant occurs in only 15%-35% of possible opportunities, natural immune defenses of the mother, fetus, or neonate may be protective against infection. The relation between antibody-dependent cellular cytotoxicity (ADCC) antibodies and HIV-1 infection was explored in 78 neonates born to HIV-infected women. More than 90% of sera had measurable ADCC titers against HIV-1IIIB. Infant titers were closely correlated with maternal titers but were independent of total IgG and total antibody reactive to the same strain in whole virus ELISA. At birth, mean ADCC antibody levels of infants or their mothers were the same for infants who were infected and those who ultimately seroreverted and remained healthy. ADCC antibody titers against HIV-1SF2 were weakly correlated with anti-HIV-1IIIB titers and did not predict protection from HIV-1 infection. High levels of anti-HIV-1 ADCC antibody at birth are not protective against vertical transmission of HIV-1.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1988

Ambulatory treatment of suspected pelvic inflammatory disease with Augmentin, with or without doxycycline.

Sixty-three women with suspected pelvic inflammatory disease were treated as outpatients with Augmentin with or without doxycycline. Initially, doxycycline was added only after a direct test for Chlamydia trachomatis was positive. Because chlamydial infections were frequent, all patients received doxycycline during the last two thirds of the study. Neisseria gonorrhoeae or Chlamydia trachomatis were recovered from 15 (65%) of 23 women classified as probably having pelvic inflammatory disease. Among 47 women reexamined after starting therapy, three rapidly became worse and were hospitalized, nine (20%) discontinued therapy because of gastrointestinal side effects, and all of the remaining 35 women who completed therapy were either cured or improved.

Adult↗
PubMed1987

Acute cholecystitis in pregnancy.

Thirty cases of acute cholecystitis in pregnancy were identified during a 12-year period. Twenty-one patients were successfully managed with medical therapy alone. Nine underwent surgical intervention, four after failing medical therapy and five as the initial approach to therapy. Surgical therapy was complicated by preterm labor and delivery in two patients undergoing surgery during the early third trimester. One patient underwent cholecystectomy during the first trimester and subsequently aborted. There were no serious complications in patients undergoing surgery during the second trimester. These data suggest that conservative medical management can be successfully used in most patients with acute cholecystitis in pregnancy.

Abortion, Spontaneous↗
PubMed1986

Experience with the routine use of erythromycin for chlamydial infections in pregnancy.

In an effort to prevent perinatal acquisition of Chlamydia trachomatis, we offered treatment with erythromycin ethylsuccinate (400 mg four times a day for seven days, given at 36 weeks' gestation) to 184 pregnant women with cervical chlamydial infections. Thirty-two women refused treatment; 24 of their infants were followed and served as the controls. Therapy was discontinued by 5 of 10 women who had gastrointestinal disturbances. Forty-seven women who completed therapy refused infant follow-up; in four (9 percent) of these women, therapy had failed to eradicate the infection. Sixty women and 59 infants completed the entire protocol; 55 (92 percent) of the women had negative cultures for chlamydia at follow-up. Chlamydial infection developed in 4 (7 percent) of the 59 infants of treated mothers, as compared with 12 (50 percent) of the 24 infants of untreated mothers; this difference was significant (P less than 0.001). With a success rate of 92 percent (98 of 107 patients) in treating maternal infection and with a relatively low intolerance rate (3 percent; 5 of 152), this regimen appears to be an effective, although not ideal, therapy for chlamydial infection in pregnant women. We conclude that in settings in which the prevalence of chlamydia infection is high, a routine program of screening pregnant women for cervical C. trachomatis, followed by treatment of those infected, would be cost effective and would reduce infant morbidity.

Chlamydia Infections↗
PubMed1986

Sulbactam/ampicillin versus metronidazole/gentamicin in the treatment of severe pelvic infections.

The clinical efficacy and safety of sulbactam/ampicillin versus metronidazole/gentamicin were compared in 39 patients with severe pelvic infections. 30 patients had severe acute pelvic inflammatory disease with peritonitis, 3 tubo-ovarian abscesses, 4 endomyometritis, and 2 posthysterectomy pelvic cellulitis. Aerobic and anaerobic cultures from the sites of infection yielded 259 micro-organisms from 38 patients; an average of 6.8 bacteria per infection (3.9 anaerobes and 2.9 aerobes). The most frequent isolates were Bacteroides spp. (21), B. bivius (13), B. disiens (8), Fusobacterium spp. (9), Peptostreptococcus anaerobius (15), P. asaccharolyticus (8), anaerobic Gram-positive cocci (17), Gardnerella vaginalis (24), Neisseria gonorrhoeae (14), alpha-haemolytic streptococci (6) and Escherichia coli (3). Clinical cure was noted in 19 of 20 patients treated with sulbactam/ampicillin and 16 of 19 treated with metronidazole/gentamicin. The sulbactam/ampicillin failure was a patient with pelvic inflammatory disease with a positive Chlamydia trachomatis culture who required antichlamydial therapy. The metronidazole/gentamicin failures included a patient with a tubo-ovarian abscess requiring surgical drainage and 2 patients with pelvic inflammatory disease requiring antichlamydial treatment. No adverse haematological, renal, or hepatic effects were noted with either regimen.

Ampicillin↗
PubMed1985

Seizures and death on a white river float trip. Report of water hemlock poisoning.

White river rafting is becoming a major summer recreational activity throughout the United States. Many people who are ill prepared physically or emotionally to survive will find themselves isolated and in extremely dangerous situations without access to medical help. In addition to the physical dangers of drowning, there are dangers that exist in the concept of "living off the land" and foraging for food. Cicuta douglasii is found in all of our western states, is extremely toxic and can easily be confused with wild parsnip or carrot. Physicians and poison control centers need to be aware of the common poisonous plants in their area and be prepared to treat cases of poisoning from these plants.

Adult↗
PubMed1981

Unsuccessful suicide by carbon monoxide: a secondary benefit of emissions control.

Emission systems and devices are required on automobile engines to reduce air pollution problems. Catalytic converters have been used on most 1975 and newer automobiles to reduce hydrocarbon and carbon monoxide (CO) emissions to a value that meets the Environmental Protection Agency requirements established for 1975 and 1976. The 1980-1981 Boise, Idaho, study shows that with a functioning catalytic converter either unmeasurable or sublethal quantities of CO appear in automobile exhaust. Thus, emissions control has produced a secondary benefit in reducing the number of suicides by CO poisoning from automobile exhaust fumes.

Adult↗