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Biomedical subjects

R G Anderson

Publications and source records attributed to R G Anderson.

193 records · Page 11Linked to original sources
PubMed1971

The formation of basal bodies (centrioles) in the Rhesus monkey oviduct.

Basal body replication during estrogen-driven ciliogenesis in the rhesus monkey (Macaca mulatta) oviduct has been studied by stereomicroscopy, rotation photography, and serial section analysis. Two pathways for basal body production are described: acentriolar basal body formation (major pathway) where procentrioles are generated from a spherical aggregate of fibers; and centriolar basal body formation, where procentrioles are generated by the diplosomal centrioles. In both pathways, the first step in procentriole formation is the arrangement of a fibrous granule precursor into an annulus. A cartwheel structure, present within the lumen of the annulus, is composed of a central cylinder with a core, spoke components, and anchor filaments. Tubule formation consists of an initiation and a growth phase. The A tubule of each triplet set first forms within the wall material of the annulus in juxtaposition to a spoke of the cartwheel. After all nine A tubules are initiated, B and C tubules begin to form. The initiation of all three tubules occurs sequentially around the procentriole. Simultaneous with tubule initiation is a nonsequential growth of each tubule. The tubules lengthen and the procentriole is complete when it is about 200 mmicro long. The procentriole increases in length and diameter during its maturation into a basal body. The addition of a basal foot, nine alar sheets, and a rootlet completes the maturation process. Fibrous granules are also closely associated with the formation of these basal body accessory structures.

Animals↗
PubMedDate not supplied

A mutation that impairs the ability of lipoprotein receptors to localise in coated pits on the cell surface of human fibroblasts.

Low density lipoprotein is taken up by cultured human fibroblasts through an endocytic process that requires the binding of the lipoprotein to specific receptors located in coated pits on the cell surface. The coated pits are discrete segments of the plasms membrane that can undergo rapid invagination to form coated endocytic vesicles. In one form of the human genetic disorder familial hypercholesterolaemia, the responsible mutation produces altered lipoprotein receptors that lack the ability to become incorporated into coated pits. Instead, these mutant receptors are scattered at random over the entire plasma membrane. Becuase of their mislocation on the cell surface, the mutant lipoprotein receptors are unable to carry their bound lipoprotein into the cell. The occurrence of this 'receptor mislocation mutation' provides strong evidence for the role of the coated pit in the receptor-mediated uptake of lipoproteins. The data also have implications for the structure and assembly of plasma membranes in mammalian cells.

Alleles↗
PubMedDate not supplied

The condensing vacuole of exocrine cells is more acidic than the mature secretory vesicle.

A number of intracellular, membrane-bound compartments in both the endocytic and exocytic pathways of eukaryotic cells have an acidic internal pH. In endocrine cells, the mature secretory vesicle has an acidic pH; secretory vesicles isolated from exocrine cells, however, appear to have a neutral pH. Recently we have used a newly developed immunocytochemical technique to map low-pH compartments in insulin-secreting islet cells with the electron microscope and find that during the maturation of the secretory vesicle there is a progressive acidification of these vesicles that begins as soon as the trans Golgi condensing vacuoles form. Now we have used this technique to examine two exocrine cells: the pancreatic acinar cell and the parotid serous cell. In both cell types, the trans Golgi condensing vacuoles are acidic and accumulate the low-pH probe to the same extent as condensing vacuoles of insulin-secreting islet cells. Unlike insulin-secreting cells, however, maturation of the granules is accompanied by a return of luminal pH to near neutrality. Therefore, although the pH of storage granules in exocrine and endocrine cells is different, the pH of the condensing vacuoles in both cells is acidic.

Amylases↗
PubMedDate not supplied

Myringoplasty. A review of 472 cases.

We reviewed the records of 472 patients who had undergone myringoplasty during an 11-year period at the Otologic Medical Group. There was a statistically significant relationship between the size of the perforation and the degree of hearing impairment, but no relationship between the degree of impairment and the complaint of tinnitus. The majority of operations were performed using the lateral surface fascia grafting technique. Those 168 operations performed postauricularly were successful in closing the tympanic membrane perforation in over 97% of the cases and in reducing the conductive deficit to 10 dB or less in 88%. There were no total sensorineural impairments, although 3% of the patients developed a high tone sensorineural impairment. Blunting in the anterior sulcus and lateral healing of the graft were very uncommon. Canal skin was used as a graft in 16% of the patients. The graft take results and hearing results were less favorable than with fascia.

Adolescent↗
PubMedDate not supplied

Comparison of continuous vs intermittent tube feedings in adult burn patients.

In an effort to determine an optimal method of utilizing the gastrointestinal tract to meet the nutritional need of burn patients, a comparison was made between continuous and intermittent delivery of lactose-free tube-fed diets in similar groups of burn-injured patients. It was found that significantly less stool frequency and time required to achieve the nutritional goal occurred in patients treated with continuous pump tube feeding over those fed intermittently.

Adolescent↗
PubMedDate not supplied

Epidural mucopyocele: diagnosis and management.

Mucopyoceles of the frontoethmoid sinuses occurring as an epidural mass are uncommon. Four patients with this condition have been managed over the last eight years by the authors. Two patients had early recurrence of their disease following carefully performed ablation and frontal craniectomy. Marsupialization, or permanently draining the ablated frontal sinus cavity into the nose, was the initial treatment of the other two patients, and subsequently the therapy of choice for all patients in this series.

Adult↗
PubMedDate not supplied

Meniere's disease: treatment with the endolymphatic subarachnoid shunt, a review of 125 cases.

A critical review of the results of treatment of 125 patients with Meniere's disease by the endolymphatic subarachnoid shunt is presented. Of the patients, 61% experienced improvement in vertigo. Hearing stabilized or improved in the majority of cases. Detailed analysis of preoperative factors did not enable prediction of the likelihood of success in an individual case. The controversy regarding surgical therapy of Meniere's disease is discussed, and the conclusion that there is a role for endolymphatic sac surgery in the treatment of Meniere's disease is presented.

Adult↗