Gastroesophageal reflux disease (GERD), extraesophageal reflux (EER) and recurrent chronic rhinosinusitis

Chronic polypoid rhinosinusitis (CRS) is a common disease, affecting approximately 16% of the adult population in the US every year. In addition to many well known predisposing factors, an association with reflux disease is hypothesized. Such an association might explain the recurrence of polyposis in the face of improved surgical techniques and postsurgical treatment of CRS. At present it is unclear whether extraesophageal reflux directly injures the sinus mucosa, whether gastroesophageal reflux leads to vagus-mediated neuroinflammatory changes, or whether both mechanisms occur separately or simultaneously. In patients suffering from recurrent CRS (n=20) and healthy volunteers (n=20), ambulatory 24 h two channel pH testing was performed. The number of reflux events, the fraction of the total time during which pH was below 4, and the reflux area index (RAI) were determined in the esophagus as well as in the hypopharynx. Patients with recurrent CRS had significantly more reflux events in the esophagus and the fraction of pH<4 and the RAI were increased up to 10-fold compared to healthy volunteers. In contrast to the esophagus, these differences were not observed in the hypopharynx. Recurrent CRS is often associated with GERD but not with EER. Recurrent disease or prolonged recovery after surgery should raise the suspicion of reflux disease as a possible triggering factor. Because GERD itself cannot be diagnosed by laryngoscopy, and because of the subjectivity of symptoms such as heartburn, the otolaryngologist should consider double-probe pH testing as the diagnostic procedure of choice.     

Identification of a Membrane Receptor for Retinol-Binding Protein Functioning in the Cellular Uptake of Retinal

Retinol-binding protein (RBP) is the transport protein that carries retinol in the circulation from the liver to its target tissues. The existence of a cell-surface receptor on the target cells, which mediates the uptake of retinol from RBP, has been known since 1975. Recently, it was identified as an integral transmem-brane protein named STRA6 that is inducible by retinoic acid in certain cancer cells. The receptor was found to be highly specific for RBP, with high affinity, and to be localized in all tissues known to require retinol for their function, particularly the pigment epithelium of the eye.     

Chronic lymphocytic leukemia presenting in the marrow of a phalanx

Systemic disease may present first in the foot. The authors present a case in which the marrow of resected bone tissue from a phalanx showed the changes of chronic lymphocytic leukemia (CLL). Subsequent blood examination confirmed this diagnosis.     

Low molecular weight heparin plus dihydroergotamine for prophylaxis of postoperative deep vein thrombosis

In a prospective, double-blind investigation of the prophylaxis of deep vein thrombosis (DVT) in patients undergoing elective major abdominal surgery, 269 patients were randomized into two groups. One hundred and thirty-two patients received a fixed combination of heparin sodium 5000 units plus dihydroergotamine mesylate 0.5 mg (H/DHE) twice a day and 137 patients received a fixed combination of low molecular weight heparin 1500 units plus dihydroergotamine mesylate 0.5 mg (LMWH/DHE) once a day as well as one injection of placebo per day. Treatment was initiated 2 h pre-operatively in both groups and continued for 7-10 days. The frequency of DVT determined by the 125I-labelled fibrinogen uptake test and phlebography was 10.3 per cent in patients receiving H/DHE and 10.4 per cent in those receiving LMWH/DHE. DVT of the femoral vein was detected in four patients of the H/DHE group and in none of the LMWH/DHE group. Intra- and postoperative blood loss did not differ significantly between both groups. Also no difference in the development of wound haematoma and injection site haematoma was found. While intra-operative volume substitution was comparable in both groups, significantly more patients under H/DHE prophylaxis received volume substitution during the postoperative phase. These results show that once-daily prophylaxis with the combination of low molecular weight heparin and dihydroergotamine is equally as effective and as safe as the twice-daily regimen using a combination of unfractionated heparin and dihydroergotamine in patients undergoing elective, major abdominal surgery. The advantages of the once-daily regimen of LMWH/DHE include greater patient acceptance, less nursing time and greater cost effectiveness, provided the new combination can be sold at a cost which maintains this advantage.     

Zur Problematik des Leistungssports bei Heranwachsenden

Ohne Zusammenfassung     

Time course of metabolic findings in coronary occlusion and reperfusion and their role for assessing myocardial salvage

The techniques currently used to assess myocardial infarction are limited in their ability to determine the amount of viable myocardium after a temporary ischemic event. Blood flow and segmental function may not necessarily demonstrate salvage, whereas metabolic parameters will determine cell survival. In an open chest dog model, short occlusion times of 20 min and subsequent reperfusion using C-11 palmitate as an index of fatty acid metabolism showed depression of fatty acid oxidation, which recovered after 3 hours of reperfusion, indicating the partial reversibility of the ischemic condition. In more extensive studies, using positron emission tomography (PET) and, as an indicator of glucose metabolism, fluoro-F-18-deoxyglucose (FDG); N-13 ammonia in addition to C-11 palmitate for the determination of blood flow; and ultrasonic crystals to measure shortening in the reperfused and control territories, the duration of occlusion was 3 h. Metabolic studies were repeated 24 h, 1 week, and 4 weeks after the ischemic injury. Reperfused viable myocardium exhibited residual glucose metabolism with FDG, whereas fatty acid oxidation remained impaired for a longer period. Gradual metabolic recovery during a 4-week period was associated with the prolonged recovery of regional function, whereas a lack of residual metabolic activity indicated that little change in function was likely to occur. Increased FDG uptake and impaired C-11 palmitate turnover are characteristic of reversibly injured tissue. Therefore, PET studies may offer a unique potential for the evaluation of therapeutic measures such as thrombolysis and early revascularization.

     

Importance of spinal noradrenergic pathways in cardiovascular reflexes and central actions of clonidine and alpha-methyldopa in the rabbit

We have examined in conscious rabbits the chronic effects of 6-hydroxydopamine (6-OHDA)-induced local lesions of the spinal noradrenaline (NA) pathways on (i) resting mean arterial pressure (MAP) and heart rate (HR), (ii) the nasopharyngeal pressor response, (iii) the sympathetic component of the baroreceptor-heart rate reflex (iv) the acute responses to intracisternal (i.c.) clonidine and alpha-methyldopa (alpha-MD), and (v) the acute NA release response produced by i.e. 6-OHDA. One month after injection of 6-OHDA (40 nmol in 4 microliters) into the first cervical spinal cord segment (C1), the NA content was reduced to 29% in C2, 45% in T4 and 61% in L3 with little non-specific damage. Basal MAP was 14% higher (P less than 0.05) than in sham-operated rabbits suggesting increased vasoconstrictor tone. Basal cardiac sympathetic tone was enhanced, but a corresponding increase in cardiac vagal tone resulted in little net effect on resting HR in the spinal NA-depleted group. Spinal NA lesions attenuated the nasopharyngeal pressor reflex by 27% in baroreceptor-intact rabbits and by 38% in sino-aortically denervated (SAD) animals. The lesion did not affect HR range, gain and BP50 of the sympathetic baroreflex. In SAD rabbits, the acute MAP responses to i.c. 6-OHDA (early hypotension, late hypertension) were not affected by spinal NA depletion, but the early fall in HR (cardiac sympathetic inhibition) was abolished. The hypotension produced by i.c. clonidine or alpha-MD was not affected by the lesion, probably because many of the NA terminals in the lower thoracic and upper lumbar cord were still intact. Our results suggest that intraspinal NA fibers have a tonic inhibitory action on spinal preganglionic vasoconstrictor and cardiac motoneurons. The spinal NA neurons affecting vasomotor tone (but not cardiac sympathetic tone) are in turn inhibited by higher vasomotor centers receiving projections from the arterial and trigeminal afferents and thereby participate in vasoconstrictor reflexes.     

Development of cytochrome P-450-altered preneoplastic and neoplastic lesions during nitrosamine-induced hepatocarcinogenesis in the rat

The expression of four cytochrome (cyt.) P-450 isoenzymes has been studied in preneoplastic and neoplastic lesions during the course of nitrosamine-induced hepatocarcinogenesis in the female Wistar rat. Following exposure to diethylnitrosamine (50 or 100 ppm in the drinking water) for 10 days, animals were taken sequentially, and the livers were analyzed for the evolution of adenosine triphosphatase deficient focal lesions. These lesions were subdivided into different phenotypes with regard to their cyt. P-450 isoenzyme expression using serial frozen sections. Our results demonstrate that about 40% of the adenosine triphosphatase-deficient lesions show concomitant alterations in their cyt. P-450 isoenzyme contents. Of these lesions, islets which are characterized by decreased levels of at least three cyt. P-450 isoenzymes show a dramatic increase in their volumetric fraction of liver tissue with progression of time. Although only very few lesions express this phenotype, the contribution to the volumetric fraction of islet tissue raises from about 2% at 10 weeks to about 60% at 35 weeks after cessation of diethylnitrosamine treatment. By contrast, lesions which express less than two alterations in cyt. P-450 isoenzyme levels develop relatively slowly. Similar results were obtained when animals were exposed continuously to diethylnitrosamine for a period of up to 8 weeks. Following treatment of islet-bearing animals with phenobarbital, an induction of cyt. P-450 isoenzymes and NADPH-cyt. P-450-reductase was observed within preneoplastic and neoplastic lesions. This induction was most pronounced in large, expansively growing nodules, a type of lesion which displayed decreased levels of these enzymes in livers of animals not treated with phenobarbital. The elevation of the cyt. P-450 isoenzymes disappeared within 2 to 3 weeks after cessation of inducer treatment. Our results indicate that a high proportion of rapidly growing lesions has assumed a constitutive deficiency in cyt. P-450 isoenzyme expression during nitrosamine-induced hepatocarcinogenesis. This deficiency, however, is not an irreversible quality, since individual cyt. P-450 isoenzymes can be markedly induced by treatment with an enzyme inducer like phenobarbital. Thus, the observed decrease in cyt. P-450 expression during development of malignancy does not result from alterations in the cyt. P-450 encoding structural genes but may rather be related to abnormalities in the function of regulatory systems of a higher order which may play a central role in the maintenance of cell homeostasis.