Acid-induced duodenal mucosal nitric oxide output parallels bicarbonate secretion in the anaesthetized pig

We recently showed the involvement of the L -arginine/nitric oxide (NO) pathway in acid-induced duodenal mucosal bicarbonate secretion in rats. The aim of the present study was to confirm this observation in pigs by direct measurements of NO production. Experiments were performed on 16 anaesthetized pigs of both sexes treated with guanethidine (6 mg kg^?1, intravenously). A duodenal segment, devoid of pancreaticobiliary influxes, was perfused with saline and the duodenal mucosal bicarbonate secretion was calculated from continuous measurements of pH and Pco₂. The perfusate contents of NO and its oxidative product nitrite were determined by chemiluminescence, after reduction of nitrite to NO. Luminal acidification with 30 mM hydrochloric acid increased the output of bicarbonate as well as NO to the perfusate, by 195 ± 45% and 106 ± 10%, respectively. These responses to acid were markedly inhibited by adding the NO synthase inhibitor N^G-monomethyl- L -arginine (L-NMMA, 0.3 mM) to the perfusate. The inhibitory effect of L-NMMA could be reversed by administration of L-arginine (3 mM). The study presents simultaneous measurements of bicarbonate and NO outputs to a duodenal luminal perfusate. The results strongly support the view that the L -arginine/NO pathway is involved in the acid-induced duodenal mucosal bicarbonate secretory response.     

Studies on calcium exchange in platelets in human diabetes

Calcium has a key role in platelet aggregation. In order to assess the role of calcium metabolism in the platelet in diabetes mellitus, calcium exchange into and out of the cytosol was investigated in platelets from eight patients with insulin-treated diabetes with a mean duration of 10 years without any clinical complications. Their mean HbAIc (glycosylated haemoglobin) was 9% (normal range 3.4-5.4%). Influx rate of 45Ca2+ was significantly increased by 35% in diabetic platelets compared with controls. The efflux rate was significantly reduced during the first 15 min but total efflux measured over 2 h was equal in diabetic and control platelets. Access to sequestered non-mitochondrial calcium in the dense tubular system was gained by permeabilization of the cells with saponin. Into cells loaded with 45Ca2+, Inositol 1, 4, 5 triphosphate (IP3) was introduced and release of the sequestered ion would be determined. In control platelets calcium release was prompt and amounted to 43%. In diabetic platelets the response to IP3 was blunted and was only 17%. The nutritional and hormonal status influenced the response to IP3 in diabetes and, to a lesser extent, in controls. In the fasting state and without insulin the release was reduced but in the fed state and after insulin the release of calcium from diabetic platelets was equal to those of controls. It is concluded that abnormalities exist in platelet calcium handling in diabetes that can be influenced by insulin and the nutritional status.(ABSTRACT TRUNCATED AT 250 WORDS)     

Native Human Serum Amyloid P Component is a Single Pentamer

Serum amyloid P component (SAP) and C-reactive protein (CRP) are members of the pentraxin protein family. SAP is the precursor protein to amyloid P component present in all forms of amyloidosis. The prevailing notion is that SAP in circulation has the form of a double pentameric molecule (decamer) whereas CRP is a single pentameric molecule.
We have investigated by gel permeation chromatography the M_r of SAP in freshly collected human serum and of SAP purified by carbohydrate affinity chromatography and anion exchange chromatography. SAP was monitored by quantitative immunoelectrophoresis and ELISA. and SAP peak fractions were analysed by use of SDS-PAGE, Western blotting, and electron microscopy. The results indicate that native SAP circulates as a single pentamer, a part of which forms complexes with C4b-binding protein. The properties of SAP changed during purification as indicated by rocket immuno-electrophoresis and electron microscopy. Thus, electron micrographs of purified SAP showed a predominance of decamers. However, the decamer form of SAP reversed to single pentamers when purified SAP was incorporated into SAP-depleted serum.     

Anti‐TB drug resistance levels and patterns among Mycobacterium tuberculosis isolated from newly diagnosed cases of pulmonary tuberculosis in Dar es Salaam,Tanzania

Anti‐tuberculosis drug resistance levels and patterns of Mycobacterium tuberculosis (Mtb) isolated from newly diagnosed tuberculosis (TB) patients in Temeke district in Dar es Salaam, Tanzania were investigated. A total of 226 Mtb isolates from 564 TB suspects with no previous history of anti‐TB treatment were tested for drug resistance against rifampicin, isoniazid, streptomycin and ethambutol on Lowenstein Jensen (LJ) medium using the proportion method. Of the 226 isolates, 22 (9.7%) were resistant to any one of the four anti‐TB drugs; nine (3.99%) isolates were isoniazid mono‐drug resistant and eight (3.54%) isolates were streptomycin mono‐drug resistant. Multi‐drug resistance, defined as resistance to both rifampicin and isoniazid, was observed in three (1.3%) isolates and two were also resistant to streptomycin and ethambutol. One (0.44%) isolate had poly resistance to isoniazid and streptomycin. The level of anti‐TB drug resistant Mtb in Temeke, an HIV endemic area, remained constant between 1995 and 2007. The level of resistance to any one of the four anti‐TB drugs was between 9.0% and 10%, resistance to individual drugs <4% and multi‐drug resistance <2%.     

Effect of inhibition of pentagastrin-stimulated acid secretion on gastric mucosal gland luminal pressure

We demonstrated previously that hydrochloric acid secreted from the gastric glands traverses the mucus layer in channels above the gland openings. The driving force for creation of these channels is most probably the hydrostatic pressure generated in the gastric gland lumen during stimulation of acid secretion. Here we investigated the effect of total inhibition of acid secretion on gland luminal pressure. Glandular pressure was measured in vivo with a pressure-sensitive microelectrode technique in Inactin^®-anaesthetized Sprague Dawley or Lewis × DA F1 rats. Glandular pressure was significantly reduced after ranitidine inhibition of acid secretion, from 17.2 ± 2.1 mmHg during pentagastrin stimulation to 11.2 ± 1.2 mmHg. This was also true when pentagastrin infusion was continued after inhibition of secretion with ranitidine. Omeprazole, however, did not significantly alter gland luminal pressure although it totally inhibited acid secretion. With continuation of pentagastrin infusion after omeprazole inhibition, glandular pressure increased significantly from 17.6 ± 3.4 to 20.1 ± 3.3 mmHg. In conclusion, total inhibition of acid secretion with ranitidine reduces but does not abolish gland luminal pressure. After omeprazole inhibition of acid secretion the gastric gland luminal pressure persisted or even increased. Since the volume secretion is lower after omeprazole administration than during pentagastrin stimulation, the outflow resistance most probably had increased after omeprazole injection. Suggestions for increased outflow resistance are narrowing in the upper part of the gland lumen by conformational changes of the cells or muscle contractions, and/or an increase in mucus secretion or viscosity.     

Squamous cell carcinomas. An immunohistochemical study of cytokeratins and involucrin in primary and metastatic tumours

The expression of cytokeratins (CK) 1, 4, 5/6, 8, 13, 18, 19 and 20 and involucrin in 42 cases of squamous cell carcinomas from various locations was examined. The tumours expressed CK5/6 in 55%, CK8 in 76%, CK13 in 43% and CK19 in 95% of cases. The CK5/6-positive primary tumours were from uterine cervix, head and neck, lung, skin, oesophagus is and urinary bladder, and the CK13-positive primary tumours were from uterine cervix, lung and vulva. Metastatic squamous cell carcinomas from head and neck more frequently expressed CK5/6 and 13, 7/7 (100%) and 6/7 (86%) compared with 3/5 (60%) and 0/5 (0%) in the primary squamous cell carcinomas. Few cases were CK1, CK4 and CK18 immunoreactive, CK20 immunoreactivity was not observed. Involucrin was expressed in 71% of tumours, and most of the involucrin-positive cells were located at the central parts of tumour cell clusters except for one case in which the peripheral cells around tumour cell clusters were positive. Thus, expression of the so-called simple epithelial markers CK8 and CK19 occurs in the majority of squamous cell carcinomas. The absence of CK20 immunoreactivity may be helpful in differential diagnosis.     

Mandibular advancement with dental appliances in obstructive sleep apnoea

The purpose of this study was to compare the effects of a modified Herbst appliance (mHA) and a muscle relaxation appliance (MR) on nocturnal breathing and body movement activity in patients with obstructive sleep apnoea syndrome (OSAS). To increase the airway space posterior to the tongue base without severely affecting the craniomandibular joint, the mHA was adjusted to anchor the mandible at 50% of maximum protrusion. MR producing an occlusal coverage but no protrusion served as a control appliance. All-night static charge-sensitive bed (SCSB) and finger oximeter recordings were done to six male patients in three conditions: first without dental device and then with mHA and with MR, in a random order, after a 2 month period of habituation. The oxyhaemoglobin desaturation events were 44.7 h^−l of recording observed during the control night, 29.6h⁻¹ with mHA ( P = 0.087). The frequency of body movements decreased from 34.9 to 20.4h⁻¹ ( P = 0.0079), respectively. MR had no significant effects either on the frequency of the desaturation events or the frequency of body movements, but the increased respiratory resistance breathing, indicating presence of partial upper airway obstruction, was reduced from 14.3 to 6.9% of the time in bed ( P = 0.022).
We conclude that 50% protrusion chosen for these experiments, produced with a mHA, brought about some alleviation of upper airway obstruction in our preselected patients, but did not lead to sufficient control of apnoea. The reduction of partial upper airway obstruction induced with a MR warrants further studies in a larger patient population.     

Prognostic Influence of Early Diagnostic Splenectomy in Hodgkin's Disease

ABSTRACT. The influence of early laparotomy with splenectomy on prognosis in patients with Hodgkin's disease who were regarded as having uncertain prognostic indices (all patients except those with lymphocytic predominance and nodular sclerosis stages IA and IIA with right-sided presentation, stage IV disease, splenomegaly or age >65 years) was evaluated in a randomized trial initiated in Jan. 1973. The patients were treated with total nodal irradiation (excluding the splenic and hepatic areas) and 33 of 69 patients were randomized to laparotomy with splenectomy. No significant difference in relapse-free or overall survival was found between the two groups after a median observation time of 85 months. Progressive or recurrent disease was as common in splenectomized as in non-splenectomized patients. Splenectomized patients with splenic tumour involvement fared worse than those without. It is concluded that diagnostic laparotomy with splenectomy is of no benefit in this clinical setting.