In recombinant Escherichia coli strains the subcellular location of human interferon (IFN) alpha 2 and a hybrid IFN alpha 1/alpha 2 was investigated by immunogold labelling techniques. The gold label was scattered throughout the cytoplasm in cells containing the gene for mature IFN alpha 2 under the control of heterologous staphylokinase sak42D transcription and translation initiation signals. In contrast, in cells containing in addition the sak42D signal peptide coding region in front of the IFN gene, the gold label was found mainly near the cell membrane and in the periplasmic space. Inclusion bodies were identified in cells accumulating IFN in the cytoplasm.

Blotting, Western↗

PubMed1991

Do arachnoid cysts grow? A retrospective CT volumetric study.

The volumes of intracranial arachnoid cysts were measured in 136 CT scans of 86 patients. Absolute and relative cyst size was calculated. Left hemisphere and middle cranial fossa location prevailed. A slight negative correlation of relative cyst size with age (r = -0.21, NS) disappeared when analysis was restricted to the adult age group (greater than or equal to 20 years). After the sample was divided into two groups according to relative cyst size (cysts less than mean volume vs cysts greater than mean volume), small AC showed no correlation with age, while large AC correlated positively with age (r = 0.79, P less than 0.05). A subgroup of large AC appears to expand with time, while the majority of small AC remain unchanged.

Adolescent↗

PubMed1991

Prenatal deletion detection in a sporadic case of Duchenne muscular dystrophy without genotype information from the affected individual.

We describe the application of deletion screening by amplification of deletion-prone exons via polymerase chain reaction (PCR) in a family with a sporadic case of Duchenne muscular dystrophy (DMD). No DNA was available from the affected patient who died 12 years beforehand at the age of 18 years. Material obtained prenatally from two male fetuses exhibited an identical deletion. These findings effectively transformed a sporadic case into a familial case and a numerical carrier risk was substituted by obligate carrier status. Additionally an indirect genotype analysis was replaced by the possibility of direct DNA analysis. Genetic counselling, formerly based upon incomplete data, can now be aided by precise risk assessment.

Adult↗

PubMed1991

Linkage mapping of autosomal dominant retinitis pigmentosa (RP1) to the pericentric region of human chromosome 8.

Linkage mapping in a large, seven-generation family with type 2 autosomal dominant retinitis pigmentosa (ADRP) demonstrates linkage between the disease locus (RP1) and DNA markers on the short arm of human chromosome 8. Five markers were most informative for mapping ADRP in this family using two-point linkage analysis. The markers, their maximum lod scores, and recombination distances were ANK1 (ankyrin)--2.0 at 16%; D8S5 (TL11)--5.3 at 17%; D8S87 [a(CA)n repeat]--7.2 at 14%; LPL (lipoprotein lipase)--1.5 at 26%; and PLAT (plasminigen activator, tissue)--10.6 at 7%. Multipoint linkage analysis, using a simplified pedigree structure for the family (which contains 192 individuals and two inbreeding loops), gave a maximum lod score of 12.2 for RP1 at a distance 8.1 cM proximal to PLAT in the pericentric region of the chromosome. Based on linkage data from the CEPH (Paris) reference families and physical mapping information from a somatic cell hybrid panel of chromosome 8 fragments, the most likely order for four of these five loci and the diseases locus is 8pter-LPL-D8S5-D8S87-PLAT-RP1. (The precise location of ANK1 relative to PLAT in this map is not established). The most likely location for RP1 is in the pericentric region of the chromosome. Recently, several families with ADRP with tight linkage to the rhodopsin locus at 3q21-q24 were reported and a number of specific rhodopsin mutations in families with ADRP have since been reported. In other ADRP families, including the one in this study, linkage to rhodopsin has been excluded. Thus mutations at two different loci, at least, have been shown to cause ADRP. There is no remarkable clinical disparity in the expression of disease caused by these different loci.

Base Sequence↗

PubMed1991

Transformation theory of size judgment.

Perception of size is assessed by having observers adjust a comparison target at a fixed distance to match the size of a standard located at different distances. Results depend on instructions, target orientation, and available stimulus cues. A mathematical theory assumes that the brain performs an inverse transformation on the proximal information impinging on the retina to recover the original distal size of the target. Results depend on the target visual angle, and the effective target distance and orientation applied in performing the inverse transformation. Effective values are linked to instructions, target location, and stimulus cues. Two models are developed and successfully fit to empirical data. One emphasizes the distance parameter; the second, the orientation parameter.

Attention↗

PubMed1991

Enhanced sensitivity of "metabotropic" glutamate receptors after induction of long-term potentiation in rat hippocampus.

Stimulation of [3H]inositol monophosphate ([3H]InsP) formation by ibotenate or trans-1-aminocyclopentyl-1,3-dicarboxylic acid (t-ACPD) in rat hippocampal slices was enhanced after tetanic stimulation of the Schaffer collaterals projecting to the CA1 region (in vitro) or the perforant pathway projecting to the dentate gyrus (in freely moving animals). This effect was observed 5 h (but not 2 h) after long-term potentiation (LTP) induction and was abolished if tetanic stimulation was performed in the presence of specific antagonists of N-methyl-D-aspartate receptors. The delayed increase in excitatory amino acid-induced polyphosphoinositide (PPI) hydrolysis was accompanied by an enhanced responsiveness to norepinephrine, whereas the basal and carbamylcholine-stimulated [3H]InsP formation were unchanged. These results suggest that an increased activity of "metabotropic" glutamate receptors may contribute to the synaptic mechanisms enabling the late expression and or maintenance of LTP. Accordingly, LTP decayed more rapidly (within 5 h) in rats repeatedly injected with LiCl (60-120 mg/kg, i.p., for 10 days), a treatment that led to a reduced efficacy of ibotenate and norepinephrine in stimulating PPI hydrolysis in hippocampal slices.

Animals↗

PubMed1991

Thyrotrophin, but not forskolin, increases intracellular free calcium and calmodulin in pig thyroid cells.

The effects of TSH and forskolin were examined on intracellular free calcium ([Ca2+]i) and calmodulin in normal pig thyroid cells in culture. TSH was found to produce acute increases in [Ca2+]i in pig cells. Responses were seen at concentrations of TSH between 0.01 and 10 mU/ml. Sensitivity to TSH was greater in adherent monolayers of cells than in cell suspensions and was also greater in subconfluent rather than confluent monolayers of cells. The increase in [Ca2+]i in response to TSH represented just over a doubling in [Ca2+]i whether examined at 22 degrees C or 37 degrees C. Forskolin failed to affect [Ca2+]i. TSH increased [Ca2+]i in the absence of extracellular calcium. TSH, but not forskolin, produced a significant increase in intracellular calmodulin after 3 days of culture of cells with TSH. The increase in calmodulin was of the order of 60% and did not relate to any effect of TSH on thyroid cell number.

Animals↗

PubMed1991

The aging eye.

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Aged↗

PubMed1991

A model in Montana: ensuring access to care.

Montana's medical assistance facility (MAF) demonstration project may provide a model for other states facing problems in maintaining access to primary health care in sparsely populated areas. Under the state's guidelines, MAFs provide treatment to ill or injured persons before transporting them to hospitals and inpatient care for persons needing it for no longer than 96 hours.

Community Health Centers↗

PubMed1991

[Control arthroscopy following alloplastically augmented anterior cruciate ligament reconstruction].

97 patients who had their ACL replaced with ligamentum patellae transplant augmented with LAD were reviewed arthroscopically after an average period of 9.1 months (4-22 months). 52 patients whose metal implants have been removed are virtually symptom-free clinically (no swelling, stable knee joint, extension limitation of less than 5 degrees, less than 10 degrees limitation of flexion). Arthroscopy on these 52 patients revealed the following; no abnormalities in 37, 11 cases of cartilage lesions, 1 case of medial meniscal tear and 7 cases of LAD tears. 45 patients who have also had their metal implants removed have complaints, arthroscopy revealed the following; hypertrophy of Hoffa's fat pad in 5 cases, 3 cases of medial meniscal tears, 2 cases of lateral meniscal tears. Tears of the LAD were seen in 9 cases. In 2 cases the transplant was missing, in 5 cases the transplant was elongated and in 2 cases the transplant showed normal structure. There were cartilage lesions in 9 cases, 4 cases of synovitis and scar tissue adhesion in 3. In all there were 16 cases of LAD tears, in 9 out of these 16 cases the transplant ACL of good structure. All of this knees were stable. Control arthroscopy is routinely carried out when we remove the metal implants. This enables us to detect any early problems, such as limitation of extension or swelling, assess the success of the operation and commence the corresponding additional therapy.

Adolescent↗

PubMed1991

Science, public health and genetic services. Menary Lecture.

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Ethics, Medical↗