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Biomedical subjects

B Appel

Publications and source records attributed to B Appel.

At least 19 recordsLinked to original sources
PubMed1992

Effects of insulin and dexamethasone on lipoprotein lipase in human adipose tissue.

The mechanisms by which insulin and glucocorticoids modulate lipoprotein lipase (LPL) synthesis and degradation were examined in human adipose tissue fragments maintained in organ culture. Tissue fragments were cultured for 7 days in serum-free medium supplemented with or without insulin (7 nM) and with or without dexamethasone (30 nM), a synthetic glucocorticoid. Responses of LPL activity to both insulin and dexamethasone were obtained at doses within the physiological range. At a maximal dose, insulin increased heparin-releasable and total LPL activity (approximately 7-fold) by specifically increasing the rate of LPL synthesis (approximately 5-fold) determined by pulse labeling with [35S]methionine and [35S]cysteine and immunoprecipitation. Dexamethasone added in the presence of insulin increased heparin-releasable and total LPL activity approximately 8-fold but did not alter rates of LPL synthesis compared with insulin alone. Pulse-chase studies showed that the rate of LPL degradation was markedly slowed in the presence of dexamethasone plus insulin compared with insulin alone. These data suggest that, in human adipose tissue, insulin is essential for maintaining rates of LPL synthesis and that cortisol may play a key role in regulating human adipose tissue LPL at the posttranslational level by inhibiting the degradation of newly synthesized LPL.

Adipose Tissue↗
PubMed1991

Slow progressive bilateral posterior artery infarction presenting as agitated delirium, complicated with Anton's syndrome.

Three patients presented with an acute agitated delirium as the earliest sign of bilateral posterior cerebral artery infarction. All patients showed a unique slow progressive deterioration with a remarkably long interval between the first neuropsychological and subsequent visual and neurological symptoms, ranging from 3 to 30 days. Repeated CT scans demonstrated hypodensities in the posterior artery territory only after a long interval of 9-12 days, in case 3, and between 33 and 48 days in case 2. In the latter case MRI was still negative 33 days after onset. In 2 patients the cortical blindness was complicated with anosognosia for blindness. Clinical condition worsened progressively in all patients, leading to death, probably due to brainstem infarction. In all 3, the combination of clinical and radiological findings indicated a 'top of the basilar' distribution, which could be confirmed in two by autopsy.

Aged↗
PubMed1991

Localized craniofacial fibrous dysplasia in a young girl.

We consider here the case of a young girl presenting a cystic bone mass in the left orbital roof. Although standard X-rays at first were not convincing, the findings on the CT examination and the histological aspect of the mass were typical of fibrous dysplasia. Although the exact diagnosis of fibrous dysplasia can only be made upon precise histological examination, radiological, and more specifically CT findings, may indicate this pathology.

Child↗
PubMed1991

Post-operative maxillary cyst associated with a maxillary sinus elevation procedure: a case report.

Proper diagnosis, treatment planning, and surgical manipulation of the posterior maxilla require a thorough knowledge of the anatomy, physiology, and pathology associated with the maxillary sinus. This case report of a post-operative maxillary cyst diagnosed following routine post-operative examination of a sinus elevation procedure illustrates the need for a meticulous surgical technique, proper management of complications, and routine, long-term follow-up. With the increased utilization of sinus elevation techniques, reports of this destructive lesion may become more common.

Aged↗
PubMed1990

Arachnoiditis ossificans with arachnoid cyst after cranial tuberculous meningitis.

A 34-year-old woman developed symptomatic arachnoiditis ossificans and an arachnoid cyst as a consequence of tuberculous meningitis adequately treated 20 years before. Surgical decompression of the cyst stopped the progression of her spastic paraparesis. Pathologic examination confirmed the presence of ossification of the arachnoid.

Adult↗
PubMed1990

Multiple sclerosis in a black Cameroonian woman.

Multiple Sclerosis (MS) has never been described in Bantu South Africans whereas it does exist in mixed race South Africans. The authors report a case of MS in a Semi-Bantu black woman from Cameroon (Central Africa) who presented with a typical remitting and relapsing course with MRI and CSF findings consistent with MS.

Adult↗
PubMed1989

Early ossification within the human fetal otic capsule: morphological and microanalytical findings.

Besides the use of conventional techniques such as light and polarization microscopy, the present paper proposes the combined use of transmission electron microscopy, secondary and backscattered electron imaging, energy dispersive X-ray analysis and computed tomography for the diagnostic evaluation of ear pathology in the human fetus. These methods were used to revisit the primary calcification front of the fetal otic capsule between 16 and 23 weeks gestational age. Ultramicroscopic evaluation demonstrates similar fetal bone formation to that found in other bones of the human fetus. The formation of the endosteal and periosteal layers is a typical example of early intra-membranous ossification. The enchondral layer is made up of fibrillar bone, laid down around the calcified cartilage remnants. Microchemical analysis indicates a significantly higher Ca/P ratio in the endochondral layer with respect to the endosteum and periosteum. The consequences of a lower Ca/P ratio in the endosteal layer are discussed in view of calcium homeostasis and inner ear function.

Ear Cartilage↗
PubMed1988

Parkinsonian syndrome after cardiac arrest: radiological and neurochemical changes.

Following a cardiac arrest, a 21-year-old man developed a Parkinson syndrome. This was due to, as shown by brain computerized tomography (CT) and magnetic resonance imaging (MRI), symmetrical infarctions of the basal ganglia, especially the globi pallidi. The levels of homovanillic acid (HVA) in the CSF were lower than normal, pointing to a possible alteration of the central dopaminergic activity. An alteration of the opioid system may also be supposed because of the extremely high levels of methionine-enkephalin (Met-Enk).

Adult↗
PubMed1988

Spinal angiomas as a cause of non-traumatic paraplegia: case report.

A case is presented of a 17-year-old boy who developed paraplegia after a sudden low back pain, like a 'stab in the back', with radicular radiation into the lower limbs. No trauma preceded the onset of symptoms. The diagnosis was finally made by neuroradiological investigations (magnetic resonance imaging (MRI), myelography and CT-scan). A review of the physiopathology of spinal angiomas, extra and/or intramedullary, by exclusion of vertebral (haem) angiomas, is made.

Adolescent↗
PubMed1988

Congenital middle ear malformations.

After a profound review of normal embryology, a systematical and topographical classification of congenital middle ear malformations in general and of meatal atresia in particular is proposed; the classification of congenital aural atresia is essentially based on the recognition of two types according to the course of the facial nerve in its third segment: in type I, a normal topography of the facial nerve is found and consequently, the middle ear anomalies are rather minimal; in type II, an antero-superior displacement of the facial nerve in its third segment is recognized and the middle ear malformations are considerable worse. In this report, also attention is paid to syndromal nosology and its genetic aspects. In view of functional surgical; reconstruction, the technique of allograft canal surgery, similar to our combined approach tympanoplasty technique, is described in detail and compared with other classical techniques. Preoperative as well as postoperative problems and complications are extensively discussed. The excellent results of our technique are proposed even after 25 years of experience. An overview of cosmetic surgery techniques is given and also alternative techniques with implantable auditory prosthetic materials are summarized.

Deafness↗
PubMed1987

Xenopus tropicalis U6 snRNA genes transcribed by Pol III contain the upstream promoter elements used by Pol II dependent U snRNA genes.

We have cloned and sequenced a 977bp DNA fragment, pXTU6-2, that represents the transcription unit for a Xenopus tropicalis U6 RNA gene. This basic repeating unit is reiterated ca.500-fold per haploid genome. Oocyte injections of pXTU6-2 led to the transcription of a mature-sized U6 RNA that, however, lacked internal 2'-O-methylations. These posttranscriptional modifications of U6 RNA might be cytoplasmic and could require its association with U4 RNA to be accomplished. The low alpha- amanitin sensitivity of U6 RNA synthesis in oocytes suggested that U6 RNA is transcribed by RNA polymerase III, consistent with features of the U6 RNA molecule which also contains a Box A- like intragenic control region. Inspection of X. tropicalis, mouse and human U6 DNA upstream sequences revealed the presence of a TATA box as well as of the proximal and enhancer (octamer motif) elements contained in snRNA genes transcribed by RNA polymerase II. We propose that U6 RNAs are synthesized by a specialized transcription complex consisting of RNA polymerase III and transcription factors, some of which are very likely shared with RNA polymerase II promoters.

Animals↗