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Biomedical subjects

L Ackerman

Publications and source records attributed to L Ackerman.

At least 19 recordsLinked to original sources
PubMed2000

Family practice training in Nepal.

BACKGROUND: This article describes the health care system in Nepal and the only existing family practice (general practice) training program in that country. The majority of doctors in Nepal still have no residency training, and a specialist focus pervades. The efforts of some leading educators in Nepal led to establishment of a family practice training program in 1982, and the program now enrolls 12 residents per year, half of whom are from India. Major obstacles in education, financing, and policy must be addressed before family practice can have a meaningful presence or effect on the health care in Nepal.

Family Practice↗
PubMed1999

Pediatric dermatology.

There are a great many disorders that can affect young animals in addition to those with a hereditary component. Still, it is important to consider genodermatoses whenever a young animal presents with dermatological lesions. Fortunately, most dermatological conditions that affect young pups and kittens carry a good prognosis for diagnosis and full recovery. It is, however, important to correctly identify those animals with a poor prognosis if for no other reason than to offer supportive genetic counseling to minimize the risk of the trait being perpetuated.

Animals↗
PubMed1999

Modes of protein movement that lead to the asymmetric localization of partner of Numb during Drosophila neuroblast division.

Partner of Numb (Pon) colocalizes with the determinant Numb and is required for its proper asymmetric localization in Drosophila. How the asymmetric localization of Pon is accomplished is not well understood. Here, we show that Pon localization takes place at the protein level and that its C-terminal region is necessary and sufficient for asymmetric localization. Fusion of the Pon localization domain with green fluorescent protein (GFP) allowed monitoring of the localization process in living embryos. Upon a neuroblast's entry into mitosis, Pon is recruited from the cytoplasm to the cortex. Cortically recruited Pon can move apically or basally within the two-dimensional confines of the cortex. This movement can occur when myosin motor activity is inhibited. However, the restriction of Pon to the basal cortex requires both actomyosin and Inscuteable.

Animals↗
PubMed1996

Differential effects of the Rac GTPase on Purkinje cell axons and dendritic trunks and spines.

Neurons contain distinct compartments including dendrites, dendritic spines, axons and synaptic terminals. The molecular mechanisms that generate and distinguish these compartments, although largely unknown, may involve the small GTPases Rac and Cdc42, which appear to regulate actin polymerization. Having shown that perturbations of Rac1 activity block the growth of axons but not dendrites of Drosophila neurons, we investigated whether this also applies to mammals by examining transgenic mice expressing constitutively active human Rac1 in Purkinje cells. We found that these mice were ataxic and had a reduction of Purkinje-cell axon terminals in the deep cerebellar nuclei, whereas the dendritic trees grew to normal height and branched extensively. Unexpectedly, the dendritic spines of Purkinje cells in developing and mature cerebella were much reduced in size but increased in number. These 'mini' spines often form supernumerary synapses. These differential effects of perturbing Rac1 activity indicate that there may be distinct mechanisms for the elaboration of axons, dendrites and dendritic spines.

Animals↗
PubMed1995

Antidepressant-induced mania and cycle acceleration: a controversy revisited.

OBJECTIVE: The longitudinal course of 51 patients with treatment-refractory bipolar disorder was examined to assess possible effects of heterocyclic antidepressants on occurrence of manic episodes and cycle acceleration. METHOD: Using criteria established from life charts, investigators rated the patients' episodes of mania or cycle acceleration as likely or unlikely to have been induced by antidepressant therapy. Discriminant function analyses were performed to assess predictors of vulnerability to antidepressant-induced mania or cycle acceleration. Further, the likelihood of future antidepressant-induced episodes in persons who had had one such episode was assessed. RESULTS: Thirty-five percent of the patients had a manic episode rated as likely to have been antidepressant-induced. No variable was a predictor of vulnerability to antidepressant-induced mania. Cycle acceleration was likely to be associated with antidepressant treatment in 26% of the patients assessed. Younger age at first treatment was a predictor of vulnerability to antidepressant-induced cycle acceleration. Forty-six percent of patients with antidepressant-induced mania, but only 14% of those without, also showed antidepressant-induced cycle acceleration at some point in their illness. CONCLUSIONS: Mania is likely to be antidepressant-induced and not attributable to the expected course of illness in one-third of treatment-refractory bipolar patients, and rapid cycling is induced in one-fourth. Antidepressant-induced mania may be a marker for increased vulnerability to antidepressant-induced cycle acceleration. Antidepressant-induced cycle acceleration (but not antidepressant-induced mania) is associated with younger age at first treatment and may be more likely to occur in women and in bipolar II patients.

Adult↗
PubMed1994

Atonal is the proneural gene for Drosophila photoreceptors.

The Drosophila peripheral nervous system comprises four major types of sensory element: external sense organs (such as mechano-sensory bristles), chordotonal organs (internal stretch receptors), multiple dendritic neurons, and photoreceptors. During development, the selection of neural precursors for external sense organs requires the proneural genes of the achaete-scute complex, which encode basic-helix-loop-helix transcription factors. These genes do not, however, control precursor selection for chordotonal organs or photoreceptors, raising the question of whether other proneural genes exist or a different mechanism of neurogenesis operates. Here we show that atonal (ato), originally isolated as a proneural gene for chordotonal organs, is also the proneural gene for photoreceptors. Pattern formation in the Drosophila eye involves a succession of cell fate specifications. Of the eight photoreceptors within each ommatidium of the compound eye, the photoreceptor R8 is the first to appear in the eye imaginal disc, right behind the morphogenetic furrow. The appearance of other photoreceptors (R1-7) follows in a defined sequence that is thought to arise by induction from R8 (refs 8, 9, 11, 12). We find that photoreceptor formation requires the function of atonal at the morphogenetic furrow and that atonal is specifically required for R8 selection. Formation of other photoreceptors does not directly require atonal function, but does depend on R8 selection by atonal. Thus, photoreceptors are selected by two mechanisms: R8 by a proneural mechanism, and R1-7 by local recruitment.

Animals↗
PubMed1994

Case report 836: Malignant large cell lymphoma of sacrum.

We present a case of PLB found in the sacrum in an HIV-seropositive patient who had low back pain radiating to the lower extremities. To the best of our knowledge this is the first report of this kind. Multiple imaging techniques, including MRI, could not reliably differentiate between neoplasm and infection. Both processes were considered since the patient was not only HIV-seropositive but also was an intravenous drug abuser and had a history of TB. The biopsy revealed diffuse large cell lymphoma typical of AIDS patients. The unusual location of PLB in our patient is a characteristic feature of lymphoma in patients with AIDS and our case should increase awareness among clinicians and radiologists of this possibility.

Adult↗
PubMed1989

numb, a gene required in determination of cell fate during sensory organ formation in Drosophila embryos.

Neurons and support cells of each sensory organ in Drosophila embryos are most likely derived from a single precursor cell. This cell lineage is affected in numb mutants. Morphological alterations of sensory structures, as well as changes in the number of cells expressing cell type-specific markers, indicate that sensory neurons in numb mutant embryos are transformed into lineage-related nonneuronal support cells. Thus the numb gene controls the fate of progeny derived from sensory organ precursors. The numb gene has been isolated by the plasmid rescue method. The structure of its predicted product is discussed.

Amino Acid Sequence↗
PubMed1989

Searching for pattern and mutation in the Drosophila genome with a P-lacZ vector.

A P-element vector has been constructed and used to generate lines of flies with single autosomal P-element insertions. The lines were analyzed in two ways: (1) the identification of cis-acting patterning information within the Drosophila genome, as revealed by a lacZ reporter gene within the P element, and (2) the isolation of lethal mutations. We examined 3768 independent lines for the expression of lacZ in embryos and looked among these lines for lethal mutations affecting embryonic neurogenesis. This type of screen appears to be an effective way to find new loci that may play a role in the development of the Drosophila nervous system.

Animals↗
PubMed1988

Identification and characterization of a neuron-specific nuclear antigen in Drosophila.

An antigen found only in neuronal nuclei of Drosophila melanogaster is revealed by staining with a monoclonal antibody (Mab44C11). This antigen appears early in development, before neurons show any other signs of antigenic or morphologic differentiation, and persists throughout development. This nuclear staining permits reliable detection of neurons in developmental studies of wild-type and mutant flies. Protein immunoblot analyses and immune precipitation experiments show that the neuronal nuclear antigen is a 50-kilodalton polypeptide.

Animals↗
PubMed1988

Positive iodine-131 6 beta-iodomethyl-19-norcholesterol (NP-59) adrenal images can precede return of adrenocortical function after o,p' DDD treatment.

A patient with bilateral adrenal hyperplasia, due to the ectopic adrenocorticotrophic hormone (ACTH) syndrome, received a 3-month course of treatment with 1,1 dichloro-2(o-chlorophenyl)-2-(p-chlorophenyl)ethane (o,p' DDD), which caused adrenal hypofunction requiring steroid therapy. Eleven months later, Cushing's syndrome recurred. His CT scan showed a left adrenal gland that was enlarged and a normal-sized right adrenal gland. However, the NP-59 image showed increased uptake by both glands. Venous effluent was sampled from each adrenal vein. The plasma cortisol level from the left gland was 1392 ng/ml, and that from the right gland was 667 ng/ml. The latter value was not significantly different from the values obtained at peripheral sites (517-744 ng/ml). In the course of recovery from o,p' DDD damage, the ability of the adrenal gland to take up NP-59 may be restored before the return of its biosynthetic and secretory functions. Serial NP-59 adrenal images can anticipate the recurrence of Cushing's syndrome after adrenolytic therapy, thereby permitting early retreatment.

19-Iodocholesterol↗