Histamine depletion does not affect pancreastatin secretion from isolated rat stomach ECL cells

ECL cells co-secrete histamine and pancreastatin, a chromogranin A-derived peptide, in response to gastrin. The aim of the study was to explore possible ways to deplete ECL cells of histamine without affecting pancreastatin and to examine how histamine depletion affects pancreastatin secretion. Isolated rat stomach ECL cells (80-85% purity), prepared by counter-flow elutriation, were cultured for 48 h in the presence of alpha-fluoromethylhistidine (histidine decarboxylase inhibitor), bafilomycin A(1) (inhibitor of vacuolar-type proton-translocating ATPase) or reserpine (inhibitor of vesicular monoamine transporter). At this stage, the cells were challenged with 10 nM (EC(100)) gastrin-17 for 30 min. Histamine and pancreastatin were determined by radioimmunoassay. Maximally effective concentrations of alpha-fluoromethylhistidine, bafilomycin A(1) and reserpine were found to lower ECL-cell histamine (by 60%, 78% and 80%, respectively) without affecting pancreastatin. Basal histamine secretion was reduced in a dose-dependent manner by all three drugs. Gastrin-evoked histamine secretion was reduced greatly by the three agents, while pancreastatin secretion was unaffected. The results show that histamine can be depleted not only by inhibiting its formation (alpha-fluoromethylhistidine), but also (and more effectively) by inhibiting histamine vesicular uptake, directly (reserpine) or indirectly (bafilomycin A(1)). The results also indicate that although histamine is co-stored with pancreastatin, it is not required for either storage or secretion of pancreastatin.     

Tachyphylaxis of the ECL-cell response to PACAP: receptor desensitization and/or depletion of secretory products

BACKGROUND AND PURPOSE: Rat stomach ECL cells secrete histamine and pancreastatin in response to gastrin and pituitary adenylate cyclase-activating peptide-27 (PACAP). This study applies microdialysis to explore how ECL cells in situ respond to PACAP and gastrin. EXPERIMENTAL APPROACH: Both peptides were administered by microinfusion into the gastric submucosa. The microdialysate was analysed for histamine and pancreastatin (ECL-cell markers) and for somatostatin (D-cell marker). KEY RESULTS: Microinfusion of PACAP (0.01-0.3 nmol microl(-1)) raised microdialysate histamine and pancreastatin dose-dependently. The response was powerful but short-lived. The response to gastrin was sustained at all doses tested. It is unlikely that the transient nature of the histamine response to PACAP reflects inadequate histamine synthesis, since the pancreastatin response to PACAP was short-lived too, and both gastrin and PACAP activated ECL-cell histidine decarboxylase. Unlike gastrin, PACAP mobilized somatostatin. Co-infusion of somatostatin abolished the histamine-mobilizing effect of PACAP. However, pretreatment with the somatostatin receptor type-2 antagonist (PRL-2903) did not prolong the histamine response to PACAP, suggesting that mobilization of somatostatin does not explain the transient nature of the response. Repeated administration of 0.1 nmol microl(-1) of PACAP (1 h infusions, 1 h intervals) failed to induce a second histamine response. Pretreatment with a low dose of PACAP (0.03 nmol microl(-1)) abolished the response to a subsequent near-maximal PACAP challenge (0.3 nmol microl(-1)). CONCLUSION: The transient nature of the histamine response to PACAP reflects desensitization of the PACAP receptor and/or exhaustion of a specific storage compartment that responds to PACAP but not to gastrin.     

Mobilization of rat stomach ECL-cell histamine in response to short- or long-term treatment with omeprazole and/or YF 476 studied by gastric submucosal microdialysis in conscious rats

1. Mobilization of histamine from the ECL cells was monitored by gastric submucosal microdialysis in conscious rats. The ECL cells are known to operate under gastrin control and the purpose of the present study was to examine their in situ response to short-term (12 h) as well as long-term (28 days) hypergastrinaemia, induced by treatment with the proton pump inhibitor omeprazole. 2. Hypergastrinaemia promptly raised the histamine concentration in the microdialysate. The effect was prevented by CCK(2) receptor blockade (YF476). On day 7 of omeprazole treatment the microdialysate histamine concentration reached a peak, five times higher than before treatment. Subsequently (14 and 28 days), less histamine was mobilized. 3. Gastrin infusion (4 h) raised the microdialysate histamine concentration in a dose-dependent manner in fasted rats and freely fed rats and in rats treated with omeprazole for a week. However, while fasted and fed rats responded to low doses of gastrin, the omeprazole-treated rats required large doses of gastrin to respond. 4. When the amount of histamine mobilized was related to the serum gastrin concentration the following EC(50) values could be calculated: fasted rats 2.3 x 10(-10) M, freely fed rats 2.5 x 10(-10) M, omeprazole-treated rats 8.7 x 10(-10) M. The maximal histamine responses in the three groups were 18.4 pmol 4 h(-1)+/-0.8, 21.9 pmol 4 h(-1)+/-1.2 and 68.0 pmol 4 h(-1)+/-3.5, respectively. 5. The results suggest that ECL cells, exposed to a high gastrin concentration for a week, respond with a shift in the receptor-ligand binding affinity from high to low. Apparently, CCK(2) receptors of the ECL cells are subject to dynamic changes with respect to ligand-binding affinity.     

Transurethral resection of the prostate a review of 1111 cases

A review of 1111 transurethral resections of the prostate (TURP) revealed a mortality of 0.5% (6 patients). A stricture frequency of 3% was observed as a complication after the operation. A supplementary resection was done within one year in 9%. Transurethral resection syndrome of the prostate (TURP syndrome) occurred in two patients. Cancer incidence was 18%. Blood transfusions were given to 20% of the patients. The weight of resected prostatic tissue ranged from 4 to 115 g (mean 25 g), and was less than 20 g in 60%. Peroperative bleeding amounting to over 1800 ml occurred in 3.3% (37 patients).     

Nanostructure of the epidermal extracellular space as observed by cryo-electron microscopy of vitreous sections of human skin

The newly developed method, cryo-electron microscopy of vitreous sections, was used to observe the nanostructure of the epidermal extracellular space. The data were obtained from vitreous sections of freshly taken, fully hydrated, non-cryo-protected human skin. The extracellular space of viable epidermis contains desmosomes, expressing a characteristic extracellular transverse approximately 5 nm periodicity, interconnected by a relatively electron lucent inter-desmosomal space. The extracellular space between viable and cornified epidermis contains transition desmosomes at different stages of reorganization interconnected by widened areas expressing a rich variety of complex membrane-like structures. The extracellular space of cornified epidermis contains approximately 9, approximately 14, approximately 25, approximately 33, approximately 39, approximately 44, and approximately 48 nm thick regions in turn containing one, two, four, six, eight, eight, and ten parallel electron-dense lines, respectively, between adjacent corneocyte lipid envelopes. The eight-line approximately 44 nm thick regions are most prevalent.     

Long-lasting cholecystokinin(2) receptor blockade after a single subcutaneous injection of YF476 or YM022

Histamine-forming ECL cells in the rat stomach operate under the control of gastrin. They represent a convenient target for studying cholecystokinin-B/gastrin (CCK(2)) receptor antagonists in vivo. We examined the effectiveness and duration of action of two CCK(2) antagonists, YM022 and YF476, with respect to their effect on ECL-cell histidine decarboxylase (HDC) activity in the rat. Oral administration of subcutaneous deposition of YF476 or YM022 reduced the HDC activity. The maximum/near-maximum dose for both drugs and for both modes of administration was 300 micromol kg(-1) (effects measured 24 h after dose). At this dose and time the serum concentration of YF476 was 20 - 40 nmol l(-1). The dose 300 micromol kg(-1) was used in all subsequent studies. A single subcutaneous injection of YF476 inhibited the HDC activity for 8 weeks. The circulating concentration of YF476 remained high for the same period of time (>/=15 nmol l(-1)). Subcutaneous YM022 suppressed the HDC activity for 4 weeks. A single oral dose of YF476 or YM022 inhibited the HDC activity for 2 - 3 days. Chronic gastric fistula rats were used to study the effect of subcutaneous YF476 on gastrin-stimulated acid secretion. A single injection of YF476 prevented gastrin from causing an acid response for at least 4 weeks (the longest time studied). We conclude that a single subcutaneous injection of 300 micromol kg(-1) YF476 causes blockade of CCK(2) receptors in the stomach of the rat for 8 weeks thus providing a convenient method for studies of the consequences of long-term CCK(2) receptor inhibition.     

Orexin loss in Huntington's disease

Huntington's disease (HD) is a devastating neurodegenerative disorder caused by an expanded CAG repeat in the gene encoding huntingtin, a protein of unknown function. Mutant huntingtin forms intracellular aggregates and is associated with neuronal death in select brain regions. The most studied mouse model (R6/2) of HD replicates many features of the disease, but has been reported to exhibit only very little neuronal death. We describe for the first time a dramatic atrophy and loss of orexin neurons in the lateral hypothalamus of R6/2 mice. Importantly, we also found a significant atrophy and loss of orexin neurons in Huntington patients. Like animal models and patients with impaired orexin function, the R6/2 mice were narcoleptic. Both the number of orexin neurons in the lateral hypothalamus and the levels of orexin in the cerebrospinal fluid were reduced by 72% in end-stage R6/2 mice compared with wild-type littermates, suggesting that orexin could be used as a biomarker reflecting neurodegeneration. Our results show that the loss of orexin is a novel and potentially very important pathology in HD.     

Indication for Liver Transplantation in Young Patients with Small Intestinal NETs Is Rare?

Background

A majority of patients with small intestinal neuroendocrine tumors (SI-NETs) present with or develop liver metastases (LM). A number of treatments for LM are used clinically, including liver transplantation (LTx). Indications for LTx are under debate; young age (<65 years), absence of extrahepatic disease, resected primary tumor and limited extent of LM have been suggested as inclusion criteria for LTx with the aim to optimize outcome.

Materials and methods

From our series of 672 patients with SI-NET treated at the University Hospital in Uppsala between 1985 and 2012, we identified 78 patients according to the following criteria: <65 years of age, locoregional surgery (LRS) of the primary tumor and mesenteric metastases successfully performed, LM present but no extrahepatic disease. Baseline was chosen as the first date the following points were met: First visit to our center, LRS performed, LM present. The patients underwent treatment according to the standard clinical protocols at our center, and during this time period we did not perform or refer any SI-NET patients for LTx. Kaplan–Meier survival analyses were performed in three different groups based on hypothetical criteria for LTx.

Results

Five-year overall survival rates for patients <65 years (n = 78) and <55 years (n = 36) of age were 84 ± 8 and 92 ± 9 %, respectively. For patients fulfilling the Milan criteria (n = 33) the 5-year survival was 97 ± 6 %.

Conclusions

Most young patients (<65 years) with SI-NET and LM have a favorable survival with standardized multimodality treatment. Indeed, most survival figures reported after LTx of NET do not surpass these figures.     

Kock urinary reservoir maturation in children and adolescents: consequences for kidney and upper urinary tract.

OBJECTIVE: To study Kock reservoir maturation in children and adolescents and its effects on the kidneys and upper urinary tract. METHODS: Ten boys and 10 girls, aged 10.8-18 years, had Kock reservoir surgery for congenital urinary incontinence. They were followed for 3-10 years, divided into 3 different periods, and assessed with urography and enterocystography, the findings of which were correlated to renal function as measured by (51)Cr EDTA clearance, reservoir endoscopy and patient's history. RESULTS: The reservoir was located in the pelvis and remained in this position throughout the whole follow-up in 75% of patients and in the lower or midabdomen in 25%. Angled efferent nipple seen on enterocystoscopy or enterocystography coincided with nipple dysfunction, reservoir malposition or infrequent reservoir emptying. Upper urinary tract dilatation was detected in 84% of patients 3 months after surgery, 25% at 1 year and 30% at 2-10 years. The dilatation was improved in 56% of patients and unchanged in 25% after 1 year. The situation continued to improve at late follow-up. New focal renal scars were radiologically detected in 1 of 19 at early and in another 1 of 17 patients at late follow-up. Progression of old scars was detected in 1 of 19 at early and in 4 of 17 at late follow-up. Eight of 19 cases had deterioration of renal function with a change in the split renal function. Of these 8 patients, 7 reported infrequent reservoir evacuation. CONCLUSIONS: Kock reservoir is a useful form of urinary diversion in children and adolescents with congenital urinary incontinence. Radiological examinations are good methods of follow-up of the maturation of the pouch and its effects on the urinary tract and for detection of complications. Urinary tract dilatation is a frequent finding early after surgery but it subsides in most cases 3-12 months after surgery. Long-term efferent nipple dysfunction may be the result of angulation, reservoir stones, malposition and/or overdistension. Permanent renal damage may be due to pyelonephritis, stones, infrequent reservoir emptying or urinary obstruction. A strict regime of reservoir evacuation to avoid overdistension and nipple dysfunction and to decrease the possibility of renal function deterioration is strongly advisable in these patients. It is imperative that their own management of the reservoir is continuously supervised.     

Prediction of the volume of large prostate cancers by multiple core biopsies

OBJECTIVE: To evaluate whether large-volume prostate cancers can be predicted by means of multiple needle biopsies. MATERIAL AND METHODS: In 115 men, 8-14 (mean 10) biopsies were taken, including eight from standardized positions (apex, mid-medial, mid-lateral and base). Biopsies were reviewed, the length of the cancer measured and the percentage cancer length calculated. All men underwent radical prostatectomy. The prostatectomy specimens were totally embedded and the tumor volume was measured planimetrically. The predictive values of the number and percentage of cores positive for cancer, cancer length and percentage cancer length were calculated for tumor volumes of >4, >6 and >8 ml. RESULTS: Using univariate logistic regression, cancer length and percentage cancer length predicted tumor volumes of >4 (p<0.001), >6 (p<0.001) and >8 ml (p<0.05). These measures were better predictors of tumor volume than the number and percentage of cores positive for cancer. A biopsy cancer length of > or =30 mm and a percentage cancer length of > or =25% predicted a tumor volume of >4 ml in 95% and 93% of cases, respectively. For tumor volumes of >6 or >8 ml, predictive values were lower. Tumor volumes of <2 and <4 ml were found in 13% and 35%, respectively of men with as many as six positive cores, indicating that the number of positive cores was less useful as a predictor of tumor volume than the cancer length. CONCLUSIONS: Cancer length and percentage cancer length are significant predictors of large tumor volumes. It is recommended that the linear extent of cancer in prostate biopsies should be reported by the pathologist.