Regulation of tyrosine phosphorylation of the nicotinic acetylcholine receptor at the rat neuromuscular junction

The nicotinic acetylcholine receptor (AChR) from the electric organ of T. californica is highly phosphorylated on tyrosine residues in vivo. In contrast, tyrosine phosphorylation of the AChR in rat myotube cultures is barely detectable. To determine whether this low level of tyrosine phosphorylation of the AChR in muscle cell cultures is due to a lack of neuronal innervation, we examined tyrosine phosphorylation of the AChR in rat diaphragm in vivo. Immunofluorescent double labeling of cryostat sections of rat diaphragm using antibodies specific for phosphotyrosine or the AChR showed a direct colocalization of phosphotyrosine with the AChR at the neuromuscular junction. Using anti-phosphotyrosine antibodies, immunoblots of AChR partially purified from rat diaphragm demonstrated that the rat AChR contains high levels of phosphotyrosine. Denervation of rat diaphragm induced a time-dependent decrease in tyrosine phosphorylation of the AChR, as measured by immunocytochemical and immunoblot techniques. Tyrosine phosphorylation of the AChR occurred late in the development of the neuromuscular junction, between postnatal days 7 and 14. These studies suggest that muscle innervation regulates tyrosine phosphorylation of the AChR and that tyrosine phosphorylation may play an important role in the developmental regulation of the AChR.

Tumorigenicity of embryonal carcinoma as an assay to study control of malignancy by the murine blastocyst

A bioassay, based on tumorigenicity, has been developed to determine the mechanism whereby the blastocyst of the mouse controls malignant expression of embryonal carcinoma. The assay is based upon the incidence of tumors obtained when known numbers of cells of the 402AX strain of embryonal carcinoma are injected into strain 129 mice, compared to the incidence obtained when the same number of embryonal carcinoma cells are incorporated into Swiss-Webster blastocysts that are then injected in strain 129 animals. The results indicate that the blastocyst can regulate one embryonal carcinoma cell consistently; it may have a slight effect on three, but it cannot regulate four or five of them. The position of the embryonal carcinoma cell in the blastocyst is important. Regulation occurs if the embryonal carcinoma cell is placed in the blastocoele cavity, but enhancement of tumorigenicity is obtained if it is placed between the zona pellucida and the trophectoderm. By contrast, the blastocyst is unable to regulate a single B-16 melanoma cell placed in the blastocoele cavity, indicating a degree of specificity for the regulatory process.

Single vs. double stapling technique in colorectal surgery. A prospective randomized trial

Seventy patients after rectosigmoid resection were randomized to a rectal anastomosis either in the single or double stapling technique. There was no statistically significant difference between the two groups. A trend in favor of the double stapling technique was noted: 2.8 percent clinical leaks vs. 8.6 percent in the single stapling technique.

Laparoscopic cholecystectomy for patients who have had previous abdominal surgery

This paper reports 121 laparoscopic cholecystectomies (LC) in patients who had had previous abdominal surgery between June 1990 and August 1992. There were 93 cases with lower abdominal scar (LS) and 28 with upper or umbilicus midline scar (US). For insertion of the laparoscope in the scarred abdomen we use the conventional laparoscopic approach (CLA), the peritoneum perforation under vision approach (PP), and the open laparoscopic approach (OLA). One hundred twenty scarred abdomens were completed successfully. Conversion to an open procedure was required in one case with previous LS, because of injury of the jejunum. One postoperative intraabdominal hematoma was noted and treated with percutaneous catheter drainage. No reoperation was required and no further complications were noted. Patients who had a previous laparotomy had no substantially longer operative time or postoperative hospital stay. Revealing a total complication rate of 1.6%, this study shows that previous abdominal surgery should no longer be considered a contraindication to LC.

Molecular studies reveal that A134T, G156A and G1333A SNPs in the CD177 gene are associated with atypical expression of human neutrophil antigen-2

BACKGROUND AND OBJECTIVES

The human neutrophil antigen-2 (HNA-2) is expressed on a subpopulation of neutrophils as most subjects present a negative plus a positive HNA-2 population of neutrophils. The number of neutrophils expressing HNA-2 is variable and may increase in pregnancy, infections, myeloproliferative disorders and after G-CSF. This study investigated the presence of polymorphisms in the gene encoding HNA-2 (CD177) in individuals presenting different patterns of antigen expression and determined the association of single nucleotide polymorphisms (SNPs) with the heterogeneous HNA-2 expression.

MATERIALS AND METHODS

Flow cytometry was employed to analyse the HNA-2 expression on neutrophils from 135 healthy subjects using two monoclonal antibodies (TAG4, 7D8). Sequencing reactions were performed on subjects whose antigen expression was low (< or = 50%), high (> or = 80%) or atypical (a nonreactive population plus two distinct positive cell populations).

RESULTS

Five SNPs were detected, two of them (A793C, G1084A) were related to a low expression of HNA-2 (P = 0.031 and P = 0.004). Atypical antigen expression was observed in 5.9% (8/135) of the individuals, three nonpregnant women and five men. In these cases, the cDNA sequences revealed three SNPs (A134T, G156A and G1333A) strongly related to this atypical HNA-2 expression (P = 0.004, P = 0.006 and P < 0.0001, respectively).

CONCLUSIONS

Our data show that polymorphisms in the CD177 are associated with variations in the HNA-2 expression and may be the cause of atypical expressions.

Chronic sequels after thoracoscopic procedures for benign diseases

OBJECTIVE

Chronic pains after lateral thoracotomy are present in up to 40% of cases. Chronic sequels after thoracoscopy are less common, but nevertheless, a cause for complaints by patients. Pain often reflects a recurrence of malign disease. For this reason, we only investigated patients with benign disease.

METHODS

We retrospectively investigated the incidence of chronic sequels in a consecutive series of 161 patients who underwent thoracoscopy for benign disease and were not converted to an open procedure. The data from all 144 patients, contactable at the time of investigation, who were at least 2 months postsurgery, were analyzed.

RESULTS

Chronic sequels were present in an overall of 31.4% of patients. Patients complained of chronic pain (20.1%), numbness distal to the incision sites (16.9%) and disaesthesia (8.3%). Painkillers are taken on a regular basis by 82.8% of patients with chronic pain. The use of Staplers, as well as the number of drains (1 vs. 2) used, were statistically significant (P>0.05) for chronic sequels. All other investigated factors, such as sex, age, and length of drainage, were not significantly different in the two groups.

CONCLUSION

The thoracoscopic approach is not likely to impact on the prevalence of long-term postthoracotomy sequels, and therefore, further strengths are necessary to reduce this number.

Increased cystatin C in astrocytes of transgenic mice expressing the K670N-M671L mutation of the amyloid precursor protein and deposition in brain amyloid plaques

Cystatin C is an essential secretory cofactor for neurogenesis with potent protease inhibitor activities. Polymorphisms of cystatin C are genetically associated with Alzheimer's disease (AD), and the L68Q mutation causes hereditary cerebral hemorrhage with amyloidosis of the Icelandic type, in which cystatin C and beta-amyloid are colocalized in cortical blood vessels. To determine whether cystatin C and beta-amyloid also colocalize in brain amyloid plaques, we analyzed transgenic mice expressing the Swedish APP (SweAPP) mutation. We found high levels of cystatin C in astrocytes surrounding beta-amyloid plaques, and discrete layers of cystatin C attached to amyloid plaque cores covered by a layer of beta-amyloid. In addition, cystatin C accumulated in reactive astrocytes throughout the brain, independently of, and before the onset of, amyloid plaque formation. These results show that expression of SweAPP is associated with increased cystatin C in reactive astrocytes, and they suggest an early role of cystatin C in appositional amyloid plaque growth.

The role of laparoscopy in chronic and recurrent abdominal pain

BACKGROUND

This study was designed to determine the efficacy of laparoscopy on patients with a history of recurrent and chronic abdominal pain longer than 3 months, of unknown origin.

METHODS

From September 1990 to May 1994, we performed 66 laparoscopic treatments on 59 patients. The assessment of life quality ensured the disability score, the McGill pain questionnaire, and the visual analogue pain scale, which were completed preoperatively, then on the day of discharge, and finally at a mean period follow-up of 75.3 weeks. Laparoscopy provided diagnosis on 53 of 59 patients (89.8%).

RESULTS

All 66 attempted laparoscopic procedures were completed successfully, no conversion to laparotomy was necessary, and no postoperative complication occurred. Five out of 59 patients (8.5%) revealed no improvement of pain postoperatively, and 6 out of 56 (10.7%) still suffer from pain at the time of the follow-up.

CONCLUSIONS

The pain assessment and disability score was statistically significant postoperatively and at the time of the follow-up in relation to the preoperative score.

Renal Sinus Fat Is Expanded in Patients with Obesity and/or Hypertension and Reduced by Bariatric Surgery Associated with Hypertension Remission

Renal sinus fat is a fat depot at the renal hilum. Because of its location around the renal artery, vein, and lymphatic vessels, an expanded renal sinus fat mass may have hemodynamic and renal implications. We studied whether renal sinus fat area (RSF) associates with hypertension and whether following bariatric surgery a decrease in RSF associates with improvement of hypertension. A total of 74 severely obese and 46 lean controls were studied with whole-body magnetic resonance imaging (MRI). A total of 42 obese subjects were re-studied six months after bariatric surgery. RSF was assessed by two independent researchers using sliceOmatic. Glomerular filtration rate (eGFR) was estimated according to the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration). Patients with obesity accumulated more RSF compared to lean controls (2.3 [1.7–3.1] vs. 1.8 [1.4–2.5] cm², p = 0.03). Patients with hypertension (N = 36) had a larger RSF depot compared to normotensive subjects (2.6 [2.0–3.3] vs. 2.0 [1.4–2.5] cm², p = 0.0007) also after accounting for body mass index (BMI). In the pooled data, RSF was negatively associated with eGFR (r = −0.20, p = 0.03), whereas there was no association with systolic or diastolic blood pressure. Following bariatric surgery, RSF was reduced (1.6 [1.3–2.3] vs. 2.3 [1.7–3.1] cm², p = 0.03) along with other markers of adiposity. A total of 9/27 of patients achieved remission from hypertension. The remission was associated with a larger decrease in RSF, compared to patients who remained hypertensive (−0.68 [−0.74 to −0.44] vs. −0.28 [−0.59 to 0] cm², p = 0.009). The accumulation of RSF seems to be involved in the pathogenesis of hypertension in obesity. Following bariatric surgery, loss of RSF was associated with remission from hypertension.

Subxiphoidal videomediastinoscopy for diagnostic access to the anterior mediastinum

Access to the anterior mediastinum from the epigastric region through the retrosternal space, performed with a videomediastinoscope, is described. The method can be used to release the lower lobes of the thymus in transcervical thymectomy as well as for the diagnosis of retrosternal masses of uncertain origin on either side of the anterior mediastinum.

Tyramine pressor sensitivity in healthy subjects during combined treatment with moclobemide and selegiline

OBJECTIVE

The objectives of this double-blind study were to assess the tolerability and i.v. tyramine pressor response during combined treatment with moclobemide and selegiline.

SUBJECTS

Two parallel groups of 12 healthy male and female subjects were treated with 200 mg moclobemide or 5 mg selegiline b.d. for 14 days. On Day 7, selegiline or moclobemide was added to the other treatment. IV tyramine pressor tests were conducted at baseline and at steady state during mono- and combined treatment.

RESULTS

Treatment with moclobemide and selegiline alone was well tolerated, whereas combined treatment led to a slight increase in adverse events. Tyramine pressor sensitivity during moclobemide, selegiline and moclobemide + selegiline treatment was enhanced, on average, by 2.4-, 1.3- and 8.4-times, respectively.

CONCLUSION

Although combined treatment with moclobemide and selegiline was well tolerated, the supra-additive potentiation of the tyramine pressor effects means that dietary restriction of tyramine intake will be necessary during such combination therapy.

Results and prognostic factors after resection of pulmonary metastases

One hundred and fifty-nine thoracotomies were performed in 122 patients with pulmonary metastases. The patients' ages ranged from 2 to 76 years, and 13 patients were younger than 18 years. The primary tumour was carcinoma in 83 cases, sarcoma in 29 cases and melanoma in 10 cases. The primary tumour in children was osteogenic sarcoma (6 patients), Ewing's sarcoma (2 patients) and Wilms' tumour (2 patients). With a minimum follow-up of 2 years, an actuarial 5-year survival rate of 38% was observed for carcinoma and 28% for sarcoma. Four of the children survived disease-free for 3 years or more after pulmonary metastasectomy. The primary tumour in these cases was osteogenic sarcoma and Ewing's sarcoma. A statistically significant difference in survival was found between the groups of carcinoma and sarcoma, but the prognosis for melanoma patients was markedly worse. In carcinoma patients the main prognostic factor was the duration of the disease-free interval. The actuarial postthoracotomy survival in patients with osteogenic sarcomas was 31% at 5 years, and 18% at 5 years in soft-tissue sarcomas. The size of the lesions, activity and disease-free interval correlated with survival in the osteogenic sarcoma group, and the number of lesions in the soft-tissue sarcoma group. An aggressive surgical approach towards pulmonary metastatic disease thus appears to be justified.

Intraoperative application of high-frequency ventilation

High-frequency pulsation (HFP), a modified high-frequency jet ventilation (HFJV) technique, was applied intraoperatively as an alternative to conventional inter mittent positive-pressure ventilation in 16 patients undergoing major thoracic operations. Gas exchange and hemodynamic stability were maintained at a frequency of 300 cycle/min. Surgical maneuvers were easier because the lungs were almost completely immobilized.

Treatment of postpneumonectomy empyema

Postpneumonectomy empyema with or without (bronchopleural) fistula is an infrequent but serious, and often life-threatening complication. In 20 of our patients postpneumonectomy empyema was discovered. The time interval between original operation and discovery of the empyema varied from 9 days to 9 years. In two cases, the empyema had been found and treated initially at another hospital but not adequately, so that at the time of treatment by us the bronchopleural fistula had already been present for 8 and 19 years. In 13 cases a bronchial stump fistula was discovered. In five patients the fistula was successfully closed endoscopically with glue. In one patient closure was performed by transmediastinal stump resection, in three patients with a fistula thoracoplasty was performed. In three patients we achieved closure by transposition of pedicled muscle flaps. In one of these patients a septic condition could be mastered by performing window thoracotomy. Two patients without fistula were successfully treated with irrigation, and two further patients with thoracostomy. In one patient recovery was achieved by medication after puncture. Two patients died of sepsis and after thoracoplasty. If a fistula is present, drainage with irrigation and endoscopical glueing should be the initial treatment. This should be followed by resection of the bronchial stump. If there is no fistula or if the stump is too short thoracostomy is the treatment of choice. If it is not successful thoracoplasty has to be performed.

Studies in experimental canine cirrhosis: hemodynamic alterations with emphasis on degree of spontaneous porto-systemic shunting

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Human neutrophil alloantigen-1a, -1b, -2, -3a and -4a frequencies in Brazilians

Human neutrophil reactive antibodies may cause clinical disorders such as transfusion-related acute lung injury, febrile transfusion reactions, alloimmune neonatal neutropenia, immune neutropenia after stem cell transplantation, refractoriness to granulocyte transfusion, drug-induced neutropenia and autoimmune neutropenia. Using the granulocyte immunofluorescence test by flow cytometry, the phenotypic frequencies of the human neutrophil alloantigens (HNA)-1a, -1b, -2, -3a and -4a were determined in 100 healthy Brazilian persons. Neutrophils were separated from blood samples by sedimentation, centrifugated and incubated with HNA-specific alloantibody plus fluorescein isothiocyanate-labeled F(ab')(2) fragments of anti-human IgG. The results showed that the phenotype frequencies of HNA-1a, -1b, -2a, -3a and -4a were 65%, 83%, 97%, 95% and 94%, respectively. We detected that neutrophils from 17% of Brazilians typed positive only with anti-HNA-1a (HNA-1a/a), 35% only with anti-HNA-1b (HNA-1b/b) and 48% reacted with both antibodies (HNA-1a/b). The frequencies found for HNA-1a and -1b were quite similar to that reported among Africans and American-Africans, but different from those found in Japanese and Chinese. In addition, our data showed that the frequencies of HNA-2, -3a and -4a in Brazilians were comparable with those observed in Caucasians. The determination of HNAs frequencies among populations with distinct racial backgrounds is important not only for anthropological reasons, but also for neonatal typing in suspected cases of alloimmune neutropenia or when patients are severely neutropenic.

Delayed diagnosis of malignant tumors missed at laparoscopic cholecystectomy

BACKGROUND

The aim of this study was to compare the significance of routine examinations prior to laparoscopic cholecystectomy (LC) with intraoperative abdominal investigation. Preoperative evaluation becomes increasingly important when laparoscopic procedures are performed for the removal of gallstones because other intraabdominal diseases may coexist in these patients, mimicking biliary tract disease.

METHODS

Over the last 6 years, we treated 816 patients with symptomatic cholecystolithiasis using LC. Prior to surgery, routine tests such as upper abdominal ultrasonography, chest radiography, and standard laboratory blood tests were carried out.

RESULTS

Despite these routine tests, coexisting colonic cancers escaped detection in four out of 816 cases. This indicates a risk of more "missed pathologies" during the course of laparoscopic operations compared to standard laparotomy.

CONCLUSION

The risk of missing coexisting diseases during laparoscopic operations has to be minimized by placing additional emphasis on careful evaluation of anamnesis. Physical examination and additional laboratory tests--such as analysis of tumor markers and blood in the stool--combined with complete abdominal ultrasonography, gastroscopy, and/or complete colonoscopy should be performed prior to LC.

[Mediastinal CT-staging of bronchial carcinomas]

Forty-three patients with proven bronchogenic carcinoma were evaluated with computed tomography (CT) to search for mediastinal and broncho-pulmonary nodal metastases. Definitive staging was achieved by thoracotomy (34 patients) and mediastinoscopy or transbronchial nodal sampling (9 patients). Three parameters of lymph node appearance on CT were studied to improve the sensitivity and specificity of CT in detecting malignancy in bronchogenic carcinoma: 1) node size, 2) node location and 3) border regularity and definition. 762 clearly defined nodes were studied by CT - 391 metastatic and 371 non metastatic. The most useful CT parameters were node size over 10 mm, and node location, which results in a sensitivity of 80% and a specificity of 88%. A combination of all 3 CT parameters increased sensitivity to 82% and specificity to 90%. These results show clearly, that size is not the only relevant CT-parameter in successful preoperative identification of mediastinal nodal metastases.

Plasma concentrations and tissue uptake of free amino acids in dogs in sepsis and starvation: effects of glucose infusion--some effects of low alimentation

The plasma concentrations of substrates, together with transhepatic and transgut balances, have been studied in six control and eight septic awake fasted dogs. Four severely ill septic dogs (typically fluid in chest and/or abdomen, extensive peritonitis, respiratory difficulties) had high concentrations of threonine, glycine, tyrosine, lysine, histidine, tryptophan, and triglycerides (p less than or equal to 0.05). The other septic dogs (less severely ill) showed fewer and less pronounced alterations in the plasma substrates (aspartate and tryptophan were elevated, p less than or equal to 0.05). The infusion of glucose increased the concentration of glucose, lactate, and pyruvate and depressed the concentrations of most amino acids in both normal and septic dogs. Threonine, asparagine, glutamine, leucine, isoleucine, alpha-aminobutyrate, and tyrosine were significantly depressed in the severely ill septic dogs (p less than or equal to 0.05). In the normal dogs most amino acids were removed by the liver, with alanine accounting for approximately 40% of the total. Glutamine removal was negligible. In the septic dogs hepatic removal of amino acids was variable; livers of two severely ill septic dogs did not remove amino acids. In the control dogs glucose infusion (0.015--0.017 g/kg/min) tended to lower hepatic removal of amino acids. Hepatic dye removal in the septic dogs was always very poor. In the gut glutamine was removed and alanine, glutamate, glycine, and ammonia produced, but the overall sum of amino acid uptake was negligible in both the control and septic dogs. The ratio of tryptophan to the sum of valine, isoleucine, leucine, tyrosine, and phenylalanine concentrations was greatly elevated in all septic dogs in which it was measured. The free concentrations of amino acids in the liver, heart, and muscle tissues were grossly elevated in the low intravenous alimented septic state relative to the fasted normal state, whereas the tissue concentrative ability as measured by nonmetabolizable amino acids, alpha-aminoisobutyrate and cycloleucine, was not similarly increased. Sepsis clearly alters plasma and tissue concentrations, and in some instances hepatic uptake of amino acids.