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Biomedical subjects

M Post

Publications and source records attributed to M Post.

At least 55 records · Page 3Linked to original sources
PubMed1987

Suprascapular nerve entrapment. Diagnosis and treatment.

Nine patients were found to have suprascapular nerve entrapment confirmed by electromyographic studies after the diagnosis was suspected. Eight patients who had a surgical release of the suprascapular ligament had good and excellent results. Except in rare cases, a positive electromyogram (EMG) including a delayed nerve conduction (using a coaxial needle) is necessary confirming evidence of the need for surgical treatment. The recommended surgical technique involves detaching the trapezius muscle from the spine of the scapula and opening the space overlying the suprascapular ligament. The trapezius is retracted cephalad while the supraspinatus is retracted caudad. This exposure avoids injury to the spinal accessory nerve and promotes a rapid rehabilitation. Suprascapular nerve entrapment should be suspected and included in the differential diagnosis of ill-defined shoulder pain.

Adult↗
PubMed1986

The cellular mechanism of glucocorticoid acceleration of fetal lung maturation. Fibroblast-pneumonocyte factor stimulates choline-phosphate cytidylyltransferase activity.

The cellular mechanism by which glucocorticoids stimulate phosphatidylcholine biosynthesis has been studied in the fetal rat lung in vivo and in cultured fetal rat lung cells of varying levels of complexity. Administration of dexamethasone to pregnant rats at 18 days gestation resulted in a significant increase in saturated phosphatidylcholine content in fetal lung 24 h after injection. Dexamethasone administration increased the activity of fetal lung choline-phosphate cytidylyltransferase by 34%. It had no effect on the activities of fetal lung choline kinase and choline phosphotransferase. Exposure of fetal lung type II cells in organotypic cultures (which contain both type II cells and fibroblasts) to cortisol resulted in a 1.6-fold increase in the incorporation of [Me-3H]choline into saturated phosphatidylcholine. The activities of the enzymes in the choline pathway for the de novo biosynthesis of phosphatidylcholine were not significantly altered except for a 105% increase in choline-phosphate cytidylyltransferase activity. Treatment of monolayer cultures of fetal type II cells with cortisol-conditioned medium from fetal lung fibroblasts resulted in a 1.5-fold increase in saturated phosphatidylcholine production. This effect correlated with a doubling of choline-phosphate cytidylyltransferase activity. Additional evidence that this stimulatory action is mediated by fibroblast-pneumonocyte factor, produced by fetal lung fibroblasts in response to cortisol, was obtained. The factor was partially purified from cortisol-conditioned medium of fetal lung fibroblasts by gel filtration and affinity chromatography. Based on biological activity, a 3000-fold purification was obtained. Stimulation of saturated phosphatidylcholine synthesis in type II cells by fibroblast-pneumonocyte factor was maximal within 60 min of incubation. Pulse-chase experiments indicated that the stimulatory effect was correlated with an increased conversion of choline phosphate into CDP choline. Moreover, the enhanced phosphatidylcholine formation by fetal type II cells in response to fibroblast-pneumonocyte factor was accompanied by decreased levels of cellular choline phosphate. These findings further support the concept that glucocorticoid action on surfactant-associated phosphatidylcholine synthesis occurs ultimately at the level of the alveolar type II cell and involves fibroblast-pneumonocyte factor which stimulates the activity of choline-phosphate cytidylyltransferase.

Animals↗
PubMed1986

Reciprocal autocrine and paracrine regulation of growth of mesenchymal and alveolar epithelial cells from fetal lung.

The regulation of DNA synthesis in 19 day rat fetal lung epithelial (alveolar type II) and mesenchymal (fibroblast) cells by protein growth factors has been studied. In each case a single growth factor is capable of stimulating 3H-thymidine incorporation into DNA: platelet-derived growth factor in the case of the alveolar type II cell and epidermal growth factor in the case of the fetal lung fibroblast. We hypothesize that these results indicate that the type II cell endogenously produces progression activities (i.e., epidermal growth factor-like and somatomedin-like activity) while the fibroblast produces competence (i.e., platelet-derived growth factor-like) and progression (i.e., somatomedin-like activity). The latter is in keeping with previous observations with skin fibroblasts. To test the above hypothesis, the effect of fetal lung fibroblast-derived conditioned media upon the growth of fetal alveolar type II cells has been determined. The results indicate that, indeed, such media contain competence activity for this cell type. The mitogenic activity was further characterized as heat-sensitive, trypsin-sensitive, and has an apparent molecular weight of 30,000 Daltons. It is not synthesized by 19 day fetal liver, kidney or skin fibroblasts and its synthesis is higher in lung fibroblasts isolated from 19 day fetuses as compared to those isolated on day 16 or day 22.

Animals↗
PubMed1986

Impingement syndrome. A review of late stage II and early stage III lesions.

From 1980 to 1984, 72 patients with impingement syndrome were treated by anterior acromioplasty before they developed rotator cuff tears. Follow-up evaluations averaged 23 months (range, five to 48 months). The average age was 42 years (range, 23-61 years). Preoperatively, 80% of the patients had pain at rest; the other 20% complained of pain during moderate activity. At the time of follow-up examination, 89% showed significant improvement, while 11% remained unchanged. Thirty-seven percent of the patients had varying degrees of muscle weakness preoperatively; of these, 71% were improved, 21% were unchanged, and 8% had a further decrease in the range of motion postoperatively. The results indicate that anterior acromioplasty is an excellent procedure for relief of pain due to impingement. Additionally, beneficial results were obtained in range of motion and muscle strength. In only a few select cases was lateral clavicle excision or tenodesis of the long head of the biceps necessary. Caution is advised in allowing return to strenuous activity unless the patient has recovered adequate strength in the cuff musculature.

Acromion↗
PubMed1986

Reliability of Andreasen's thought, language and communications disorder scale.

The study of disordered thinking has been hampered by a lack of clinical instruments aimed at the measurement of thought disorder. Andreasen has proposed a rating scale for thought disorder (TLC) and reported on its reliability and preliminary aspects of its validity. In our study, a psychiatrist and physician assistant rated 98 psychiatric inpatients using the TLC and BPRS. Interrater reliability ranged from 0.35 to 0.80 (weighted kappa) on 18 aspects of thought disorder and one global item. The order of reliability for the 18 individual items was strongly correlated between the Andreasen sample and our own (r = 0.77). While the BPRS thought disorder scale was significantly related to the global rating of thought disorder on the TLC (r = 0.71), only half of the variance in thought disorder measured by the TLC was accounted for by the BPRS factor. Thus, this study supports Andreasen's contention that the TLC is a reliable instrument and suggests that the instrument may provide additional information about thinking disorders.

Communication↗
PubMed1986

Synovectomy in hemophilic arthropathy. A retrospective review of 17 cases.

Seventeen patients with severe hemophilic synovitis were reviewed for an average of 59.6 months after surgical synovectomy to record radiographic progression of arthropathic changes, frequency of hemarthroses, and range of motion. There were 12 knees and five elbows in the study. Most joints showed some radiographic progression of the arthropathy. In aged patients, two knees progressed to end-stage disease. The frequency of hemarthroses was greatly decreased in all joints and especially in the elbow. Range of motion was preserved for most knees but was reduced significantly for the elbow. Three of five elbows had additional procedures. This factor may be responsible, in part, for lost motion in the elbow as compared to the relatively good results in the knee having had true synovectomy. While the incidence of bleeding is significantly decreased after surgical synovectomy, it is not necessarily associated with a cessation of the progression of joint pathology. Reduced incidence of bleeds following postsurgical synovectomy may serve to delay reconstructive operations until a later period in life. Eventually, the disease proceeds to end-stage arthropathy as joint function correspondingly decreases with age. Early surgical synovectomy for intractable chronic synovitis is recommended as a useful measure in the management of hemophilic arthropathy. Patients should be treated conservatively with therapeutic doses of factor concentrate replacement for a reasonable period of time in an effort to obviate surgical treatment.

Adolescent↗
PubMed1985

Glucocorticoids affect the synthesis of pulmonary fibroblast-pneumonocyte factor at a pretranslational level.

Glucocorticoids accelerate fetal lung maturation by acting on the fetal lung fibroblast to induce the synthesis of fibroblast-pneumonocyte factor which in turn stimulates pulmonary surfactant synthesis by the alveolar type II cell. We have studied the site of glucocorticoid regulation of fibroblast-pneumonocyte factor synthesis in primary cultures of fetal rat lung fibroblasts. Conditioned media from fetal rat lung fibroblasts exposed to cortisol stimulate [Me-3H]choline incorporation into saturated phosphatidylcholine by primary cultures of fetal rat lung alveolar type II cells. This effect is blocked by the presence of actinomycin D during the first, but not the second, 24 h of incubation of the fibroblasts with cortisol. Cycloheximide blocks this effect if present during either the first or second 24 h of incubation. We fractionated mRNA from fetal rat lung fibroblasts incubated in the presence or absence of dexamethasone and observed that cell-free translation products from a fraction of approximately 500 bases possess biological activity in the bioassay. Such activity is only present in cell-free translation products of mRNA isolated from fibroblasts treated with dexamethasone. These results suggest that glucocorticoids act at a pretranslational level to induce production of fibroblast-pneumonocyte factor and that the primary translation products are biologically active.

Animals↗
PubMed1985

Compartmentalization of 11-oxidoreductase within fetal lung alveolus.

The role of 11-oxidoreductase in the cellular process of fetal lung surfactant production and its localization within the alveolar domain have been investigated. In organotypic cultures of fetal rat lung, cortisol and cortisone markedly stimulate saturated phosphatidylcholine synthesis by the alveolar type II cell; a 10-fold excess of 11-ketoprogesterone blocks the bioactivity of cortisone. Both cortisol and cortisone also stimulate fibroblast-pneumonocyte factor production, whereas 11-ketoprogesterone blocks the effect of cortisone, but not of cortisol, suggesting that cortisone stimulation of fibroblast-pneumonocyte factor production depends on its conversion to cortisol by 11-oxidoreductase. A survey of the cells that are present in the alveolar domain revealed that 11-oxidoreductase activity is only present in the fibroblast. Localization of both 11-oxidoreductase and fibroblast-pneumonocyte factor production within the same cell emphasizes the significance of 11-oxidoreductase in the regulation of fetal lung surfactant production.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1985

Current concepts in the diagnosis and management of acromioclavicular dislocations.

Not all complete dislocations of the acromioclavicular joint should be treated by one method alone. A classification of acromioclavicular dislocation is presented and is based upon the pathology of the injury. Grade I sprain results from a mild force that causes tearing of only a few fibers of the acromioclavicular joint. Grade II sprains are caused by a moderate force with a rupture of the capsule and acromioclavicular ligament. Grade III sprains result from a severe force that ruptures both the acromioclavicular and coracoclavicular ligaments and causes a dislocation of the joint. Grade IV dislocation may be associated with an avulsion fracture of the coracoclavicular ligament from the inferior lateral clavicle, severe tearing or other injury to the soft-tissue envelope about the lateral clavicle, or a buttonhole injury of the lateral clavicle. Grade V dislocation refers to a posterior displacement of the lateral clavicle from any cause, while Grade VI relates to an inferior lateral clavicle displacement. Grades I, II, and most Grade III injuries can be treated conservatively. The indications for open treatment of Grade III injuries are reviewed. It is recommended that Grade IV and most Grade V and VI dislocations be managed with open methods.

Acromioclavicular Joint↗
PubMed1985

Rotator cuff repair with carbon filament. A preliminary report of five cases.

Carbon filament-polylactic acid (CPA) is useful in closing large and massive tears of the rotator cuff. CPA was not used to fill a large gap between the cuff edge and raw bone. In the small number of shoulders (five) repaired with CPA, the best results were obtained in first-time operations. In two patients who had total acromionectomies, the functional results were poor, as expected. CPA-assisted cuff repairs have not yet been shown to be significantly better than repairs with conventional techniques.

Acromion↗
PubMed1984

Pool sizes of precursors for phosphatidylcholine formation in adult rat lung type II cells.

The pool sizes of the choline intermediates and cofactors involved in the CDPcholine pathway were studied in alveolar type II cells from adult rat lung. The choline phosphate pool was much larger than both the choline and CDPcholine pools. Kinetic analysis of the pool sizes revealed that cholinephosphate cytidylyltransferase catalyzes a non-equilibrium reaction. These results are consistent with the idea that cholinephosphate cytidylyltransferase regulates the choline flux into phosphatidylcholine in adult rat lung type II cells.

Animals↗
PubMed1984

The rate-limiting reaction in phosphatidylcholine synthesis by alveolar type II cells isolated from fetal rat lung.

The rate-limiting reaction in the formation of phosphatidylcholine by type II cells isolated from fetal rat lung was examined. Studies on the uptake of [Me-3H]choline and its incorporation into its metabolites indicated that in these cells the choline phosphate pool was much larger than both the choline and CDPcholine pools. Chemical measurements of the pool sizes showed that the choline phosphate pool was indeed much larger than the intracellular choline and CDPcholine pools. Pulse-chase studies with [Me-3H]choline revealed that labelled choline taken up by the cells was rapidly phosphorylated to choline phosphate and that the radioactivity lost from choline phosphate during the chase period appeared in phosphatidylcholine. Little change was observed in the labelling of CDPcholine during the chase period. These results indicate that cholinephosphate cytidylyltransferase catalyzes a rate-limiting reaction in phosphatidylcholine formation by fetal rat lung type II cells.

Animals↗
PubMed1984

Effect of fibroblast-pneumonocyte factor on the synthesis of surfactant phospholipids in type II cells from fetal rat lung.

The effect of fibroblast-pneumonocyte factor on the formation of surfactant-associated phospholipids was studied in fetal rat lung type II cells in primary culture. Exposure of the cells to fibroblast-pneumonocyte factor enhanced the incorporation of radioactively labelled choline, glycerol and palmitate into total and saturated phosphatidylcholine. Fibroblast-pneumonocyte factor also stimulated the formation of phosphatidylglycerol from labelled glycerol and palmitate but did not significantly affect the synthesis of the other phospholipids. This indicates that fibroblast-pneumonocyte factor specifically stimulates the production of surfactant lipids in fetal lung.

Animals↗
PubMed1984

Insulin acts on the fibroblast to inhibit glucocorticoid stimulation of lung maturation.

The effects of insulin and cortisol on saturated phosphatidylcholine synthesis are examined in fetal type II cell cultures and in mixed cell cultures containing type II cells and fibroblasts. In 19-day fetal rat lung type II cell cultures, 100 nM cortisol and 2 nM insulin have no significant effect. Fibroblast-pneumonocyte factor results in enhanced saturated phosphatidylcholine synthesis by fetal type II cells. The significant stimulatory effect of cortisol in mixed-cell cultures is abolished in the presence of insulin or of monoclonal antibodies to fibroblast-pneumonocyte factor. Incubation of type II cells with conditioned media from fibroblasts exposed to cortisol results in increased saturated phosphatidylcholine synthesis. This process is not stimulated when type II cells are incubated with conditioned media from fibroblasts exposed to insulin and cortisol (or to insulin alone). These observations demonstrate that insulin inhibits cortisol induction of lung maturation and suggest that this antagonism results from an inhibitory effect of insulin on the elaboration of fibroblast-pneumonocyte factor by fetal lung fibroblasts.

Animals↗