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Biomedical subjects

J Adler

Publications and source records attributed to J Adler.

At least 109 records · Page 6Linked to original sources
PubMed1992

Stereotaxic radiosurgery for brain metastases: the importance of adjuvant whole brain irradiation.

Stereotaxic radiosurgery delivered from a modified 4 MV linear accelerator was used to treat 47 brain metastases in 27 patients at Stanford. Response was assessed in 41 lesions. Histopathologies included adenocarcinoma (24 lesions), renal cell carcinoma (9 lesions), melanoma (6 lesions), and squamous cell carcinoma (2 lesions). Follow-up ranged from 1.0-16.5 months, with a median of 5.0 months. Radiographic local control was achieved in 88% of the lesions. Three patients developed enlarging contrast-enhancing lesions in the radiosurgical field; one of these was biopsied and revealed necrosis with no viable tumor. Adjuvant whole brain irradiation (10 patients) was associated with regional intracranial control in 80% of patients. This was statistically superior (p = 0.0007) to the regional intracranial control rate achieved when radiosurgery alone was employed (6 patients). Most patients reported resolution of their neurologic symptoms, and were able to discontinue dexamethasone without impairment of neurologic function.

Adult↗
PubMed1992

Epi-fluorescence microscopy and image analysis used to measure diffusion coefficients in gel systems.

A method using epi-fluorescence microscopy and image analysis has been developed to follow and quantify the diffusion of fluorescent compounds through gels. Two mathematical approaches were employed to calculate diffusion coefficients. The spatial resolution provided by the fluorescence microscope allowed diffusion to be followed over very short distances; accordingly diffusion coefficients were obtained within minutes, even for slowly diffusing systems. The method was successfully applied to the diffusion of macromolecules into agar, carbopol and mucus gel systems.

Algorithms↗
PubMed1992

DnaK, DnaJ, and GrpE are required for flagellum synthesis in Escherichia coli.

The DnaK, DnaJ, and GrpE heat shock proteins are required for motility of Escherichia coli. Cells deleted for dnaK or dnaJ, or with some mutations in the dnaK or grpE gene, are nonmotile, lack flagella, exhibit a 10- to 20-fold decrease in the rate of synthesis of flagellin, and show reduced rates of transcription of both the flhD master operon (encoding FlhD and FlhC) and the fliA operon (encoding sigma F). Genetic studies suggest that DnaK and DnaJ define a regulatory pathway affecting flhD and fliA synthesis that is independent of cyclic AMP-catabolite gene activator protein or the chemotaxis system.

Bacterial Proteins↗
PubMed1992

Inoculation of C6 glioma cell suspension into the brain of adult rats: morphological study.

The C6 astrocytoma cell line was inoculated intracerebrally as suspension into the rat brain. Tumors were allowed to grow 2 to 60 days and their development was studied on coronal sections at these survival times. Tumor cells developed intraparenchymal solid tumor at the implantation site. C6 cells also filled out the needle track-area and spread into meninges. At 2 days postimplantation (2 DPI), tumor cells were observed to infiltrate recipient's brain directly from the implantation site or via perivascular spaces of adjacent cerebral blood vessels. Some cells escaped from the implantation channel during transplantation. They spread diffusely via cerebrospinal fluid (CSF) in leptomeningeal regions over the brain surface. At 10 DPI, the tumor mass invaded the adjacent brain parenchyma as well as cerebral ventricles (CV) and C6 cells could spread intraventricularly. At 30 DPI, tumor extremely increased its size and its growth was expansive. It exhibited areas of necrosis and later on, at 60 DPI, inoculated rat brains revealed large empty pseudocysts resulting from decay of necrotic tumor masses.

Animals↗
PubMed1992

Survival in a cohort of human immunodeficiency virus-infected tuberculosis patients in New York City. Implications for the expansion of the AIDS case definition.

BACKGROUND: The occurrence of pulmonary tuberculosis in human immunodeficiency virus (HIV)-infected persons is believed to represent a less severe stage of HIV-related disease with a more favorable prognosis than other acquired immunodeficiency syndrome (AIDS)-defining conditions; therefore, it has been excluded from the AIDS definition established by the Centers for Disease Control (Atlanta, Ga) criteria. METHODS: To determine the prognosis of patients with HIV-related tuberculosis, we assessed the clinical, immunologic, and HIV infection status of a cohort of male subjects aged 20 to 44 years who were hospitalized with tuberculosis but without AIDS in New York City hospitals from 1985 through 1986, and we determined their mortality through May 1991. RESULTS: The 58 patients who agreed to participate were largely (90%) nonwhite and had a high prevalence of pulmonary tuberculosis (90%) and HIV infection (53%). Patients who were HIV seropositive had significantly lower CD4 cell counts (median, 0.136 x 10(9)/L; range, 0.013 x 10(9) to 2.314 x 10(9)/L vs median, 0.765 x 10(9)/L; range, 0.284 x 10(9) to 2.333 x 10(9)/L), and, during the follow-up period, an 83% mortality rate that was 7.5 times higher than the 11% rate in seronegative subjects. Survival analyses revealed that for all HIV-seropositive subjects the probability of death at 30 months was 72% and the median survival was 21 months (95% confidence interval, 15.5 to 26.5 months), while for HIV-seropositive subjects with CD4 cell counts of 0.2 x 10(9)/L or less, the probability of death at 30 months was 92% and the median survival was 15.75 months (95% confidence interval, 14.0 to 17.6 months). CONCLUSION: The prognosis for patients with HIV-related pulmonary tuberculosis is poor, and those with CD4 cell counts of 0.2 x 10(9)/L or less have survival patterns similar to that of patients with AIDS. We believe that these data support the expansion of the AIDS case definition to include persons with both pulmonary tuberculosis and severe HIV-related immunosuppression.

AIDS-Related Opportunistic Infections↗
PubMed1991

Auditory stimulus processing at different stimulus intensities as reflected by auditory evoked potentials.

The influence of stimulus intensity on the components of auditory evoked potentials was investigated at different levels of attention and task relevance in six healthy adult subjects. A negative component with a latency of 130 msec (N130) was produced by stimuli applied as targets or nontargets in a random sequence. The N130 amplitude had an inverse U-shaped relationship to stimulus intensity, with its maximum value at a stimulus intensity of 70 dB SL. The P300 latency showed a U-shaped relationship to stimulus intensity and obtained its minimum value at 70 dB. Thus, evoked-potential equivalents of cognitive auditory stimulus processing could be shown to be loudness driven and to have highest amplitudes or shortest latencies at a stimulus loudness of 70 dB SL.

Adult↗
PubMed1991

Results of surgery for extratemporal partial epilepsy that began in childhood.

Thirty-five consecutive patients who underwent surgery for intractable extratemporal seizures originating in childhood are described. Candidates for surgery were selected on the basis of clinical criteria, neurodiagnostic imaging, and an electroencephalographic investigation that included the use of sphenoidal electrodes and long-term monitoring. Invasive preoperative monitoring was not used. Our results, with respect to the control of seizures and behavioral improvement, are comparable with series in which data from invasive recordings were used in the selection process. Sixty-three percent of the 35 patients (76.5% of those operated on after the introduction of long-term electroencephalographic monitoring) became either seizure free or experienced a reduction in their frequency of seizures by at least 75%. The favorable outcome in this group of patients strengthens the argument for early operation in children with intractable epilepsy, even when the seizure focus is outside the temporal lobe.

Adolescent↗
PubMed1991

A single amino acid substitution alters conductance and gating of OmpC porin of Escherichia coli.

We have reconstituted into liposomes outer-membrane fractions from Escherichia coli strains which express OmpC porins with altered pore properties. Single-channel experiments were performed with the patch-clamp technique on blisters generated from the reconstituted liposomes. Our goal was to identify positively the activity pattern of OmpC in our reconstituted system. The properties of the parent strain were compared to those of a strain whose OmpC porin has a single amino acid substitution in a postulated transmembrane segment. The parent and the mutant strain each exhibit a cation-selective channel of high open probability and gating to closed levels of various amplitudes. However, the mutant channel appeared to be 9 to 30% larger in unit conductance. It tended to close and reopen most often in groups of three units, as opposed to two units in the parent channel. The results are discussed in terms of the observed phenotype and of their implication as to the structure-function relationship of the porin channels.

Bacterial Outer Membrane Proteins↗
PubMed1991

Biomechanical management of children and adolescents with Down syndrome.

The authors describe the podiatric biomechanical management of the child and adolescent with Down syndrome. They also present an overview of the genetics, general characteristics, orthopedic problems, and gait of these patients. They discuss the various approaches to the biomechanical problems associated with the syndrome, and present two case histories that demonstrate common considerations in the treatment of the patient with Down syndrome.

Abnormalities, Multiple↗
PubMed1991

[Psoriasis in a female chimpanzee].

Psoriasis, a widespread genodermatosis in Homo sapiens, also appears in primates. We report on a female chimpanzee in Leipzig Zoo. After years of captivity the animal developed erythematosquamous, highly hyperkeratotic, lesions, some confluent, on the knees, elbows, back of the hands and feet and on the forearms and the seat, which showed histologically characteristic features of psoriasis. It may be that both previous infections and psychic stress resulting from social isolation had caused eruption of the disease. In the literature single cases of psoriasiform dermatoses have also been described in other species of monkeys and even in a springer spaniel. Nonetheless, the search for an animal model of psoriasis vulgaris is still going on.

Animals↗
PubMed1990

Mechanosensitive ion channels of E. coli activated by amphipaths.

Mechanosensitive channels have been found in more than 30 cell types, including bacterial, yeast, plant and animal cells. Whether tension is transferred to the channel through the lipid bilayer and/or underlying cytoskeleton is not clear. Using the patch-clamp method, we found that amphipathic compounds, which are molecules having hydrophobic and hydrophilic character with positive, negative or no net electric charge at pH 7, could slowly activate the mechanosensitive channels of giant Escherichia coli spheroplasts, with effectiveness proportional to their lipid solubility. The cationic or anionic amphipaths were able to compensate for each other's effect. After a channel was activated by an amphipath of one charge, if that amphipath was gradually replaced by one with the opposite charge, the channel first inactivated before reactivating. These findings support the view that the mechanical gating force can come from the surrounding lipids.

Cell Membrane↗
PubMed1990

Ion channel activities in the Escherichia coli outer membrane.

The electrical properties of Escherichia coli cells were examined by the patch-clamp technique. Giant cells or giant spheroplasts were generated by five different methods. By electron micrographic and other criteria we determined that the patches are most likely from the outer membrane. We regularly observed currents through at least two types of channels in this membrane. The first current is mechanosensitive and voltage-dependent, and can be observed in single gene mutants of the known major porins (ompF, ompC, phoE, lamB); this channel may represent a minor porin or a new class of outer membrane protein. The possible identity of the second, voltage-sensitive channel with one of the known outer membrane proteins is being explored. The high-resistance seals consistently formed on these patches and the presence of gated ion channels suggest that most of the pores of the outer membrane are not statically open, as commonly held, but are closed at rest and may be openable by physiological stimuli.

Bacterial Outer Membrane Proteins↗