A comparative evaluation of fibreoptic bronchoscopy versus C-MAC® D-BLADE-guided videolaryngoscopy for nasotracheal intubation under general anesthesia in oropharyngeal carcinoma surgery patients

PURPOSE

Nasotracheal intubation (NTI) is required for surgery in oropharyngeal (OP) carcinoma patients, but it may be challenging because of distorted anatomy, mucosal congestion, and increased risk of bleeding. Flexible bronchoscopy (FB)-guided NTI is preferred in these cases but has limitations. In this randomized controlled study, we sought to compare C-MAC® D-BLADE-guided videolaryngoscopy (VL) (Karl Storz SE & Co. KG, Tuttlingen, Germany) with FB for NTI under general anesthesia in patients with OP carcinomas.

METHODS

We randomized a total of 100 patients with OP carcinoma and El-Ganzouri's risk index (EGRI) < 7 to undergo NTI under general anesthesia with FB (n = 50) or C-MAC D-BLADE-guided VL (n = 50). The primary outcome was the total intubation time. We also recorded the time to glottis view, nasal intubation difficulty scale (NIDS) score, best percentage of glottis opening score, and complications.

RESULTS

The median [interquartile range (IQR)] total intubation time was shorter with VL than with FB (total intubation time, 38 [26-43] sec vs 60 [52-65] sec; difference, -20 sec [95% confidence interval (CI), -27 to -11]; P < 0.001). Similarly, the median [IQR] time to glottis view was shorter with VL compared to FB (8 [6-9] sec vs 22 [14-25] sec; difference, -13 sec [95% CI, -17 to -10]; P < 0.001). The median NIDS score was higher with VL (difference, 2 [95% CI, 2 to 3]; P < 0.001). The incidences of airway trauma (two cases with FB vs seven with VL; P = 0.30) and postoperative sore throat (ten cases in both groups; P = 0.56) were similar.

CONCLUSION

Compared to FB, C-MAC D-BLADE-based VL reduced the total time for nasal intubation oropharyngeal carcinoma patients, potentially representing an acceptable alternative in selected cases.

TRIAL REGISTRATION

CTRI.nic.in (2018/11/0162830); first submitted 8 November 2018.

The minimum effective dose (ED90) of prophylactic oxytocin infusion during cesarean delivery in patients with and without obesity: an up-down sequential allocation dose-response study

BACKGROUND

Obesity is associated with greater oxytocin requirement during labor induction or augmentation. There are scant data exploring the intra-operative requirement during cesarean delivery in patients with obesity, and none comparing it with those without obesity. We evaluated the minimum effective dose (ED90) of an oxytocin infusion to achieve adequate uterine tone during cesarean delivery in patients with and without obesity.

METHODS

Patients (body mass index ≥30 kg/m2 represented patients with obesity) undergoing cesarean delivery using subarachnoid block were included. This prospective dual-arm dose-finding study used a 9:1 biased sequential allocation design. Oxytocin infusion was initiated at 13 IU/h at cord clamping in the first patient of each group. Uterine tone was graded as satisfactory or unsatisfactory by the obstetrician four minutes after initiation of the infusion. The dose of oxytocin infusion for subsequent patients was determined according to the response of the previous patient in the group. Oxytocin-associated side effects were evaluated. Dose-response data for the groups was evaluated using log-logistic function and ED90 estimates derived from fitted equations using the delta method.

RESULTS

The ED90 of oxytocin was significantly higher for patients with obesity (n = 40) compared with those without obesity (n = 40) [25.7 IU/h, 95% CI 18.6 to 32.9) vs. 16.6 IU/h, 95% CI 14.9 to 18.3)]; relative ratio 1.55 [95% CI 1.09 to 2.01] (P = 0.019).

CONCLUSIONS

Patients with obesity require a higher intra-operative oxytocin infusion dose rate to achieve a satisfactorily contracted uterus after fetal delivery when compared with patients without obesity.

Calculation of effective dose of phenylephrine bolus for treatment of post-spinal hypotension in pre-eclamptic patients undergoing caesarean section - a non-randomised controlled trial

BACKGROUND

Patients with pre-eclampsia require smaller vasopressor doses compared with those with normotension for management of post-spinal hypotension during caesarean section. However, the literature has little evidence as to the phenylephrine dose required for patients with pre-eclampsia.

METHODS

Fifty patients, with either pre-eclampsia or normotension, and developing post-spinal hypotension during caesarean section under spinal anaesthesia, were studied. Women in both groups did not receive prophylactic vasopressors. The first patient in each group received phenylephrine 50 µg to treat the first episode of hypotension, defined as fall of systolic blood pressure ≥20% from baseline or an absolute value <100 mmHg. If hypotension was corrected within one minute it was considered a 'success'. The doses for the subsequent patients were determined by responses to all previous patients, according to a variation of Narayana's rule for the up-down sequential allocation method.

RESULTS

The 95% effective dose (ED95) and 50% effective dose (ED50) of phenylephrine was 41.7 µg (95% CI 33.8 to 49.6 µg) and 29.1 µg (95% CI 26.0 to 32.2 µg) respectively in the pre-eclampsia group, and 64.9 µg (95% CI 54.1 to 75.7 µg) and 47.3 µg (95% CI 39.7 to 54.9 µg) respectively in the normotensive group. The proportionate reduction in phenylephrine dose ranged from 33% (95% CI 18 to 44%) to 40% (95% CI 19 to 52%).

CONCLUSION

Patients with pre-eclampsia may need a 33% to 40% reduction in the first phenylephrine bolus dose, compared with patients with normotension, for the treatment of the first episode of post-spinal hypotension.

Use of Pearson and Spearman correlation testing in Indian anesthesia journals: An audit

Background and Aims

Correct usage and interpretation of biostatistical tests is imperative. Aim of the present article was to evaluate the use of "correlation test" for biostatistical analysis in two leading Indian journals of anesthesia and sensitize the readers regarding its correct usage.

Material and Methods

A prospective analysis was done for all original articles using the correlation test (Pearson or Spearman) that were published in "Indian Journal of Anaesthesia" (IJA) or "Journal of Anaesthesiology and Clinical Pharmacology" (JOACP) in the years 2019 and 2020.

Results

Amongst all included original studies, correlation test were used in 6% (JOACP) and 6.5% (IJA) respectively (averaged for the years 2019 and 2020). Correlation test was usedinappropriately) for evaluating an aim of prediction/agreement/comparison, rather than association, in 25% and 10% instances each (JOACP and IJA). In both JOACP and IJA, there were high rates of using and interpreting results without citing 95% confidence intervals (CIs) of correlation coefficient (88% and 90%, respectively), P value for significance of the association (50% and 90%, respectively), or coefficient of discrimination (88% and 70%, respectively). In majority of the instances, test to ascertain presence of mandatory prerequisites such as normal distribution of data could not be found (62% and 90%, respectively).

Conclusion

The complete potential of correlation test in exploring research questions is probably underappreciated. Further, even when used, its application and interpretation are prone to errors. We hope that the present analysis and narrative is a well-timed appropriate step in bridging the gaps in existing knowledge regarding use of correlation test in national anesthesia literature.

Establishing Trimester-Specific Haemoglobin A1c Reference Intervals in Pregnant Women: A retrospective study of healthy South Asian women with normal pregnancy outcomes

Objectives

This study aimed to define trimester-specific haemoglobin A1c (HbA1c) reference intervals in healthy, pregnant South Asian women.

Methods

This retrospective study was conducted at St. Stephen's Hospital, Delhi, India, between January 2011 and December 2016. Healthy pregnant women were compared to a control group of healthy non-pregnant women. Pregnant participants had term deliveries of babies with appropriate gestational weights. The HbA1c levels were calculated in terms of non-parametric 2.5 and 97.5 percentiles for women in first (T1), second (T2) and third (T3) trimester groups. Statistical tests were used to obtain the normal HbA1c reference values and were considered significant when P <0.05.

Results

This study included a total of 1,357 healthy pregnant women and a control group of 67 healthy, non-pregnant women. Pregnant women had a median HbA1c of 4.8% (4-5.5%) or 32 mmol/mol (20-39 mmol/mol); non-pregnant women had a median HbA1c of 5.1% (4-5.7%) or 29 mmol/mol (20-37 mmol/mol; P <0.001). The HbA1c levels for the T1, T2 and T3 groups were 4.9% (4.1-5.5%) or 30 mmol/mol (21-37 mmol/mol), 4.8% (4.5-5.3%) or 29 mmol/mol (20-34 mmol/mol) and 4.8% (3.9-5.6%) or 29 mmol/mol (19-38 mmol/mol), respectively. The HbA1c values were significant when comparing T1 versus T2 (P <0.001), T1 versus T3 (P = 0.002) and T1 versus the non-pregnant group (P = 0.001). However, T2 versus T3 was not significant (P = 0.111).

Conclusion

Compared to non-pregnant women, HbA1c levels were lower in pregnant women, despite women in the T2 and T3 groups having a higher body mass index than the women in the T1 and non-pregnant groups. Further research is recommended to understand the factors responsible and validate these findings.

Overview of statistical methods usage in Indian anaesthesia publications

Background and Aims

Despite the importance of statistics being well established for medical research, it remains a neglected area of understanding and learning. The present survey aimed to examine the use of various statistical methods in a two-year sample (2019-2020) of representative Indian anaesthesia journals and compare it with an international top-ranked journal.

Methods

The literature survey included analysis of 748 original articles from 'Indian Journal of Anaesthesia' (179), 'Journal of Anaesthesiology Clinical Pharmacology' (125) and 'Anesthesia & Analgesia' (444) published over the period. Original research articles were identified from the table of contents of each issue. Articles were assessed for statistical methods, categorised as being descriptive, elementary, multivariable, advanced multivariate or diagnostic/classification.

Results

Compared to Anesthesia & Analgesia, the Indian journals (considered together) had a significantly greater use of mean (standard deviation) (91.2% versus 70%) and percentages (79.5% versus 67.6%) (P = 0.000 each); and lesser for Wilcoxon (5.4% versus 14.6%) and Pearson/Spearman (5.1% versus 13.5%) correlation tests (P = 0.000 each), multivariable tests including various regression methods (P < 0.001), classification/diagnostic tests [Receiver operating characteristic (ROC) curve analysis, P = 0.022; sensitivity/specificity, P = 0.000; precision, P = 0.006; and relative risk/risk ratio, P = 0.010] and a virtual absence of complex multivariate tests.

Conclusion

The findings show limited use of advanced complex statistical methods in Indian anaesthesia journals, usually being restricted to descriptive or elementary. There was a strong bias towards using randomised controlled designs. The findings suggest an urgent and focussed need on training in research methodology, including statistical methods, during postgraduation and continued medical training.

The development of QERM scoring system for comprehensive assessment of the Quality of Empirical Research in Medicine - Part 1

Purpose

Whereas a large number of features are mentioned to connote the quality of medical research, no tool is available to comprehensively measure it objectively across different types of studies. Also, all the available tools are for reporting, and none includes quality of the inputs and the process of research. The present paper is aimed to initiate a discussion on the need to develop such a comprehensive scoring system (in the first place), to show that it is feasible, and to describe the process of developing a credible system.

Method

An expert group comprising researchers, reviewers, and editors of medical journals extensively reviewed the literature on the quality of medical research and held detailed discussions to parse quality at all stages of medical research into specific domains and items that can be assigned scores on the pattern of quality-of-life score.

Results

Besides identifying the domains of the quality of medical research, a comprehensive tool for scoring emerged that can be possibly used to objectively measure the quality of empirical research comprising surveys, trials, and observational studies. Thus, this can be used as a tool to assess Quality of Empirical Research in Medicine (QERM). The expert group confirmed its face and content validity. The tool can be used by the researchers for self-assessment and improvement before submission of a paper for publication, and the reviewers and editors can use this for assessing the submissions. Published papers can also be rated such as those included in a meta-analysis.

Conclusion

It is feasible to devise a comprehensive scoring system comprising domains and items for assessing the quality of medical research end-to-end from choosing a problem to publication. The proposed scoring system needs to be reviewed by the researchers and needs to be validated.

Neonatal outcomes following phenylephrine or norepinephrine for treatment of spinal anaesthesia-induced hypotension at emergency caesarean section in women with fetal compromise - a randomised controlled study

BACKGROUND

Norepinephrine is as effective as phenylephrine for management of spinal anaesthesia-induced hypotension. Most of the studies comparing these vasopressors have been conducted in healthy pregnant women undergoing elective caesarean section. In the current study, we tested the null hypothesis that there is no difference in neonatal outcome when phenylephrine or norepinephrine is used to treat spinal anaesthesia-induced hypotension in women undergoing emergency caesarean section for fetal compromise.

METHODS

Patients undergoing caesarean section for fetal compromise who developed spinal anaesthesia-induced hypotension were randomised to receive phenylephrine 100 μg or norepinephrine 8 μg for treatment of each hypotensive episode, defined as systolic blood pressure <100 mmHg. Umbilical cord arterial and venous blood samples were obtained for blood gas analysis. The primary outcome measure was umbilical artery pH.

RESULTS

One hundred patients (50 in each group) were studied. There was no significant difference in umbilical artery pH between the two groups (mean difference 0.001; 95% CI -0.032 to 0.034). The number of hypotensive episodes, vasopressor boluses required, the incidence of bradycardia, heart rate and blood pressure trends following vasopressor administration, and the incidence of nausea/vomiting were not significantly different between groups.

CONCLUSION

Phenylephrine 100 μg and norepinephrine 8 μg were not significantly different in terms of neonatal outcome when administered as intravenous boluses for treatment of spinal anaesthesia-induced hypotension in parturients undergoing emergency caesarean sections for fetal compromise.

Current Status and Future of End-Stage Kidney Disease in Gulf Cooperation Council Countries: Challenges and Opportunities

There is a paucity of data on epidemiology along with an incomplete registry of end-stage kidney disease (ESKD), nephrologist workforce, and variability among the countries of Gulf Cooperation Council (GCC). The study is an observation, descriptive study which aimed to describe current ESKD burden, nephrologist density, and kidney care infrastructure in GCC. Responses to a questionnaire-based survey obtained from representatives of the Nephrology Societies of GCC countries were analyzed. The categorical variables were compared using Chi-square test. A P = 5% was considered as significant. The mean prevalence of ESKD per million populations (pmp) was 551, highest in Oman (1000/pmp), least in Qatar (347/pmp). Predominant etiology in GCC was diabetes mellitus (DM) and hypertension (HTN) (100%, each), followed by chronic glomerulonephritis (66.7%). A transplant registry was maintained by all GCC countries. Hemodialysis (HD) (67.2%) was the most opted modality of kidney replacement therapy (KRT), followed by kidney transplantation (22%) and peritoneal dialysis (9.6%); 1.0% of patients opted for conservative management. Unplanned initiation of HD was three times more common. The access distribution among incident and prevalent HD patients respectively was (i) nontunneled central catheter (nTCC) (58.7 ± 36.6 vs. 1.5 ± 1.5), (ii) tunneled central catheter (23.5 ± 29.9 vs. 33.6 ± 10.0), and (iii) arteriovenous fistula (17.3± 14.4 vs. 57.8 ± 11.86). Death and transplantation were the reasons for dropout from HD. GCC has adequate kidney care infrastructure. There are 1686 nephrologists [range: Bahrain 9, Kingdom of Saudi Arabia (KSA) 1279]. Qatar, KSA, and Kuwait provide training in kidney biopsy; all countries except Bahrain have formal training programs for nTCC placement. ESKD prevalence is high, DM, HTN; glome-rulonephritis (GN) is the most common causes. The need for KRT is expected to rise in GCC. HD is the predominant KRT modality with a high prevalence of dialysis catheters as vascular access.

Tumor-host interface in oral squamous cell carcinoma: Impact on nodal metastasis and prognosis

PURPOSE

To evaluate tumor-host interface in oral squamous cell carcinoma (OSCC) by the Brandwein-Gensler histological risk score (BG risk score); to assess its association with clinicopathological features and impact on survival outcomes in a contemporary cohort staged as per AJCC 8th edition pTNM classification.

METHODS

This retrospective cohort study at a tertiary care centre included 178 cases of OSCC treated by primary surgical resection from 2013 to 2016. Pathological lymph node status, disease-free survival (DFS), overall survival (OS) were assessed.

RESULTS

BG risk score assessment categorized 25 (14%) cases as low-risk, 93 (52%) as intermediate-risk, and 60 (34%) as high-risk. BG risk score category progression from low to intermediate to high risk was associated with an incremental risk of worsening pN status, DFS, and OS. BG risk score categories significantly demarcated 2-year DFS (96% in low-risk, 51.6% in intermediate-risk, 15% in high-risk; p < 0.001) and OS (96% in low-risk, 66.7% in intermediate-risk, 31.3% in high-risk; p < 0.001). On stratified analysis, BG risk score could further demarcate prognosis in early (I/II) and late (III/IV) stage subgroups (p < 0.001). Multivariate analysis indicated the prognostic impact of BG risk score categories to be additional to, and of equal magnitude to, impact of pTNM stage.

CONCLUSIONS

BG risk score is a powerful prognostic tool in OSCC additional to pTNM staging. It can enable risk stratification and inform decisions regarding post-surgical adjuvant treatment. It is undertaken with routine histopathological evaluation, with no increased expense or turnaround time. A case is made for its inclusion in OSCC reporting guidelines.

Environment-friendly route for stable aqueous dispersion of reduced graphene oxide for heat transfer application

A simultaneous functionalization and reduction route to prepare stable dispersion of reduced graphene oxide from graphene oxide has been described. Diethanol amine has been introduced for the first time as an environment friendly reducing agent in a simple reflux reaction. Diethanol amine acts as a reducing agent and helps to enhance the stability of dispersion, making hydrogen bonding by virtue of two functional groups. The prepared dispersion of 0.025 mg/mL concentration is stable for months together and has a zeta potential value -45 V at room temperature. UV-Vis study shows peak at 264 nm that is signatory for reduced graphene oxide. TEM images confirm spread thin sheets of graphene of few hundred nanometer lateral dimension. Thermal diffusivity studies suggest nearly 60% enhancement for the dispersion in comparison to base fluid, water. This suggests graphene dispersion is promising for heat transfer applications.

Biodiesel surrogates: achieving performance demands

Synthesis of surrogate molecules is particularly useful for generating in sight of structural-activity relationships, understanding processes and improving the performance. In order to improve upon the physico-chemical properties of biodiesel, methyl, ethyl, isopropyl and n-butyl esters of beta-branched fatty acid have been synthesized, initiating from beta-branched alcohols. Beta-branched alcohols upon oxidation gave corresponding acids, which were converted to their esters. The synthesized esters have substantially better oxidative stability, exhibited by Rancimat oxidation induction period of more than 24 h. The cloud point of synthesized esters is < -36 degrees C, pour point is < -42 degrees C and CFPP is < -21 degrees C, which is substantially better than fatty acid methyl esters. Besides achieving the objective of better oxidative stability and improved low temperature properties, the synthesized surrogate esters have viscosity in the range of 4.2-4.6 cSt at 40 degrees C, meeting the international diesel and biodiesel standards. The cetane number of synthesized esters is 62-69, which is much better than diesel and biodiesel. The blends of the synthesized esters in diesel at 5% and 10% meet Indian standards of diesel.

Role of substance P in several models of bladder inflammation

Substance P (SP) is a peptide found in the sensory nervous system which has multiple biologic effects including stimulation of muscle contraction, pain nociception, immune cell functions, plasma extravasation and a constellation of inflammatory effects. Here we investigate the role of SP in several animals models of bladder inflammation. Using the female Lewis rat, inflammation was induced using either xylene, lipopolysaccharide (LPS) or polyinosinic-polycytidylic acid (polyIC). Inflammation occurred rapidly (4 h) and was maintained in each model for at least 7 days. Each of these protocols decreased the bladder content of immunoreactive SP by approximately 50%, suggesting enhanced release. There was no change in the urinary frequency of these animals over 3 weeks, suggesting that urinary frequency changes are not mediated by acute inflammation. We also found that the SP receptor (NK1) antagonist, (-)CP96345, was unable to block the inflammation produced by polyIC, suggesting that SP is not an obligatory mediator of immune cell stimulation in this model.

Effect of vitamin C on androgen independent prostate cancer cells (PC3 and Mat-Ly-Lu) in vitro: involvement of reactive oxygen species-effect on cell number, viability and DNA synthesis

Studies have described the protective role of vitamin C (ascorbic acid) in certain types of cancer. In this study, we report the effects of vitamin C treatment of two androgen independent prostate cancer cell lines from human (PC3) and rat (Mat-Ly-Lu or MLL) sources. In vitro treatment of PC3 and MLL with sodium ascorbate acid (0-10 mM) resulted in a decrease in cell viability and thymidine incorporation into DNA. These effects of vit. C were dose and time dependent. Ascorbate induced these changes through the production of hydrogen peroxide since addition of catalase (100-300 units/ml), an enzyme that degrades hydrogen peroxide, inhibited the effects of ascorbate on these cell lines. In contrast, superoxide dismutase, an enzyme that dismutates superoxide and generates hydrogen peroxide did not prevent ascorbate-induced changes emphasizing the involvement of reactive oxygen species (ROS) in cellular damage. That singlet oxygen scavengers such as sodium azide and hydroquinone, hydroxyl radical scavengers such as D-mannitol and DL-alpha-tocopherol did not counteract the effects of ascorbate on thymidine incorporation suggests that these free radicals are not involved in cellular damage. In conclusion, these results suggest that vitamin C inhibits tumor growth by virtue of producing reactive oxygen species. These results suggest that ascorbate is a potent anticancer agent for prostate cancer cells.

Myosin isoforms in uterine smooth muscle during pregnancy in rat

Effects of uterine stretching and physiological hypertrophy on myosin isozyme were investigated in rat during pregnancy. Both nonpregnant and pregnant rat uteri express a single myosin band on native gels. Analysis of native myosin under denaturing conditions revealed two myosin heavy chains (MHCs) with molecular mass of 204 and 200 kDa respectively. Filamin, a 240 kDa protein co-electrophoreses with myosin on native gels. No correlation is found between regulatory myosin light chain phosphorylation and pattern of myosin isozymes or the MHC. The results suggest that uterine stretching and physiological hypertrophy during pregnancy do not induce any changes in uterine myosin isozyme.

Antiproliferative effects of c-myc antisense oligonucleotide in prostate cancer cells: a novel therapy in prostate cancer

OBJECTIVES

To explore the possibility of using antisense oligonucleotide therapy for prostate cancer, we investigated the effect of c-myc-antisense-oligonucleotide (c-myc-As-ODN) in human prostate cancer cell lines such as LNCaP, PC3, and DU145.

METHODS

LNCaP, PC3, and DU145 cells were incubated in the presence of c-myc-As-ODN. Dose (0 to 10 microM) and time dependent (1 to 6 days) effects on proliferation and viability were examined by [3H]thymidine incorporation and MTT assay, respectively. Flow cytometry analysis was carried out to analyze cell cycle status by determining the DNA content in LNCaP cells. Control cultures received either c-myc-sense-ODN or scrambled (nonsense) nucleotides.

RESULTS

Time- and dose-dependent decreases in DNA synthesis and cell viability were noted for all three prostate cancer cell lines after c-myc-As-ODN treatment. Further studies using LNCaP cells indicated that these changes were accompanied by an increase in the percentage of cells with less than 2N DNA content after c-myc-As-ODN treatment. The results suggest that c-myc-As-ODN induces cell death. Comparison of a c-myc-As-ODN-treated group with a group subjected to isoleucine deprivation revealed that thymidine incorporation was almost the same in c-myc-As-ODN-treated LNCaP cells and in LNCaP cells at early S phase.

CONCLUSIONS

These results suggest that c-myc-As-ODN inhibits prostate cancer cell growth and proliferation mainly by decreasing cell viability.

Changes in myosin heavy chain (MHC) expression during pregnancy in rat uterus

Expression of myosin heavy chain (MHC) was investigated in rat uterus during pregnancy. Two MHC isoforms, SM MHCI (204 kDa) and SM MHCII (200 kDa), were resolved following the analysis of Guba Straub extract of non-pregnant and pregnant uterus using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Whereas SM MHCI showed an increase from 69.26 +/- 3.26% in nonpregnant uterus to 81.40 +/- 5.36% in pregnant uterus, the SM MHCII exhibited a corresponding decline from 30.73 +/- 3.29 to 18.59 +/- 5.36%. The native myosin separated under non-dissociating conditions and subsequently analyzed in denaturing SDS-PAGE also demonstrated two MHC isoforms with identical electrophoretic mobilities. A SDS-PAGE analysis of native myosin from pregnant rats extracted at room temperature and in the absence of proteolytic inhibitors revealed a characteristically increased proteolysis of MHC into two peptide products of 153 and 140 kDa during pregnancy. Such a proteolysis of MHC, but in very low proportions, was noticed in nonpregnant uterus too.

17 beta-estradiol induced prostatitis in the rat is an autoimmune disease

PURPOSE

Studies suggest that alteration in steroid hormone levels may be one of the factors causing nonbacterial prostatitis (NBP) in rats. We hypothesized that hormonally induced prostatitis in the rat may be an autoimmune disease. Studies were carried out to prove this hypothesis.

MATERIALS AND METHODS

We injected 17 beta-estradiol (E2; 250 micrograms/kg. subcutaneously) or vehicle into 1-year-old male rats for 30 days, and isolated and cultured the splenocytes in the presence of con-A (Experiment 1). Approximately 10(7) splenocytes were adoptively transferred into young naive syngeneic rats. To find out whether or not the inflammation is mediated by T-lymphocytes, a pure population of T-lymphocytes from E2-treated 3-month-old rats was injected into young naive syngeneic rats (Experiment 2). To rule out the possibility that the inflammation was due to con-A itself, we cross-linked some T-cells with anti-CD3 antibody before adoptive transfer (Experiment 2).

RESULTS

The recipients of splenocytes from E2-treated animals presented evidence of inflammation in terms of lymphocytic infiltration and presence of degranulated mast cells. Furthermore, we observed in these animals an increase in histamine-releasing peptide (HRP) levels, an indication of plasma extravasation. The T-cells stimulated by anti-CD3 antibody produced a similar degree of inflammation, thereby ruling out the possibility that the inflammation was due to con-A. The results also indicated that the immune response to antigen(s) is not dependent on the age of the animal but is dependent on a population of CD3+ T-cells.

CONCLUSION

Our results demonstrate that hormonal imbalance and autoimmunity in male rats produce the symptoms of nonbacterial prostatitis.

Myosin light chains in regenerating graft in chick gastrocnemii

Myosin light chains in normal and minced autografted chick gastrocnemii have been studied by disc gel electrophoresis during 70 days postgrafting period. As a result of induced mechanical trauma, the quantitative relationships between myosin light chain fractions are disturbed affecting the muscle functions.

Myosin light chains (MLCs) heterogeneity in mammalian smooth and cardiac muscle

A comparative study of myosin light chains (MLCs) has been made in the aorta, uterine and cardiac muscles (auricle, ventricle) of mice, pig, sheep and goat. Analysis of myosin light chains by sodium dodecyl polyacrylamide gel electrophoresis (SDS-PAGE) has revealed that (a) aorta myosin from mice, goat and pig has identical myosin light chains profile but pig aorta myosin lacks LC-2f; (b) uterine smooth muscle myosin depicts absence of LC-1f in sheep. Whereas satellite bands of LC-1f and LC-2f fractions are absent in pig uterine myosin, mice shows duplets for both the myosin light chains; (c) the auricular myosin in pig and goat is identical to chicken gizzard myosin used as reference and exhibits ALC-2s and ALC-1s fractions only while sheep auricular myosin lacks in ALC-1f; (d) the mice ventricular myosin depicts two satellite MLCs associated with fast migrating VLC-1s.

Loss of electrolytes during repair and regeneration of skeletal muscle

Changes in the specific conductivity and electrolytes have been studied in the leachates from normal and minced autografted chick gastrocnemii with special reference to the loss of Na+, K+, Ca2+, Mg2+ and PO(4)3- ions. The study has revealed age related modifications in the muscle membranes as well as the presence of some intrinsic regulatory mechanisms which get stimulated under the induced-stress condition. Higher ionic efflux in the regenerating muscle indicates that the anatomical regeneration does not correspond to functional regeneration of muscle membranes.

Acidic and basic protein contents in Gastrocnemii and pectoralis muscles of chick under denervation and work-induced stress conditions

Biochemical estimation of acidic and basic proteins of chick gastrocnemii (G. externus, G. medius and G. internus) and pectoralis muscles has been done under normal, denervated and work stress conditions from 1-56 days of postnatal growth. The reciprocal relationship of the two protein groups is clearly established. It is evident that muscle denervation acts as a stimulant for proteosynthetic activities and probably may also be an inhibitory factor for protein degradative reactions. During work overload stress, the rapid growth of muscles has been related to high rate of contractile activity.

Native manual tonsillectomy: A dangerous practice in Asir

One method of traditional medicine from Tihamat Asir in Southwestern region of Saudi Arabia is described. This is native manual tonsillectomy which is performed by local healers. This has not been previously reported. Children who received this treatment were admitted to Asir Central Hospital (ACH) at Abha with varying symptomatology. The practice can lead to serious complications. It is possible that this practice is more prevalent in the community than what we have seen in clinical practice.

Effects of subchronic treatment with cis-platinum on testicular function, fertility, pregnancy outcome, and progeny

Cis-platinum-based chemotherapy is known to impair spermatogenesis, but the effects of paternal cis-platinum treatment on the progeny are unknown. To study this effect, sexually mature male Sprague-Dawley rats were administered intraperitoneal injections of saline or cis-platinum (0.5 mg/kg per day) for 9 weeks. Every week, one set of control and treated animals was mated with females in proestrus. Nineteen days later, the females were subjected to laparotomy, and the numbers of corpora lutea, resorptions, and normal and abnormal fetuses were noted. In conjunction, the effects of treatment on the hypothalamo-pituitary-gonadal axis of the treated males were evaluated. Cis-platinum-treated animals failed to grow; the weights of the reproductive organs and the sperm counts declined from week 2 onward, and sperm motility was reduced throughout the testing period. Circulating and intratesticular levels of testosterone declined from week 3 of treatment and follicle-stimulating hormone levels were not affected. Serum levels of luteinizing hormone declined from week 3 and were not detectable from week 6 onward. However, the pituitary response to gonadotropin-releasing hormone was intact in all treated groups. There was no significant decrease in fertility, but a prominent increase in pre- and postimplantation losses of fetuses after cis-platinum treatment was observed. There was also a decrease in the male-to-female ratio of the offspring. A small but significant number of malformed and growth-retarded fetuses was also found among the offspring of cis-platinum-treated males. These results suggest that subchronic treatment with low doses of cis-platinum may affect progeny; such effects are seen in addition to the apparent alteration in a number of measures of reproductive function of treated males.

The mechanism of cyclosporine's action in the inhibition of testosterone biosynthesis by rat Leydig cells in vitro

We have previously demonstrated that cyclosporine inhibits testosterone (T) biosynthesis in vivo. To better understand the mechanism by which CsA inhibits T synthesis, interstitial cells were isolated from rat testes and incubated in the standard medium 199 with or without CsA (0-10 micrograms/ml) in the presence or absence of human chorionic gonadotropin (hCG, 10(-7) M) and 8-bromo cyclic AMP (cAMP, 0.5 mM) for 3 hr at 32 degrees C. The levels of cAMP and T were determined by RIA. CsA did not inhibit the basal secretion of T, but inhibited hCG-stimulated T production in a dose-dependent manner (4 ng/10(6) cells vs. 10 ng/10(6) cells at a CsA dose of 5 micrograms/ml, P less than 0.05). Radioligand binding of 125I-hLH to testicular membranes was not affected by CsA, as CsA did not compete with hCG/LH for binding sites (25-28% binding with or without CsA). Similarly, the MIX-stimulated cAMP production was not affected by CsA (24.03 +/- 1.09 vs. 20.60 +/- 0.38 pmol/10(6) cells), suggesting that CsA does not inhibit the accumulation of the second messenger. However, when interstitial cells were incubated with CsA in the presence of cAMP, a significant dose-dependent decline in T secretion was observed (7 ng/10(6) cells vs. 20 ng/10(6) cells at a CsA dose of 5 micrograms/ml). To determine whether CsA inhibits the steps beyond cAMP stimulation of T secretion, the kinetic parameters (Km and Vmax) of steroidogenic enzymes, delta 4-3 keto-17 alpha hydroxylase (17 alpha-hydroxylase), and delta 4-3 keto-17 beta hydroxy steroid dehydrogenase (17B-HSD) were determined by using Michaelis Menten analysis. Results are shown in the presence of CsA vs. no CsA: Km and Vmax values for 17 alpha-hydroxylase were (2.32 vs. 7.98 microM) and (27.96 vs. 100.97 pmol/mg protein/min), respectively. For 17B-HSD the Km and Vmax were (2.14 vs. 1.52 microM) and (15 vs. 15 pmol/mg protein/min), respectively. These results indicate that CsA inhibits the activity of 17 alpha-hydroxylase uncompetitively and 17B-HSD activity competitively. In conclusion the primary site for CsA inhibition is the cAMP stimulation and, CsA inhibits T synthesis at multiple sites.

Effect of radiation on some haematological parameters and its modification by vitamin E in chicks

White leghorn male chicks of 1 and 7 day age groups were studied for acute (2.25 Gy) gamma radiation (with or without vit. E pretreatment) induced haematological changes in the peripheral blood at days 1, 3, 5, 7, 14 and 28 postirradiation. A continuous decrease in the erythrocyte numbers was observed in the animals irradiated without vit. E treatment. The changes in haematocrit, haemoglobin, MCV, MCH and MCHC values were in line with the erythrocytic changes reflecting radiation induced damage to the erythroid elements. Animals pretreated with vit. E show lesser depression in the erythrocytic component at all the stages indicating its radio-protective influence. The significant increase in the immature RBC's in the peripheral blood in vit. E treated animals after irradiation, implies enhanced erythropoiesis.

The peptide VIP is a neurotransmitter in rat adrenal medulla: physiological role in controlling catecholamine secretion

1. The perfused adrenal gland of the rat was used to establish the identity of a non-cholinergic substance involved in splanchnic nerve-mediated secretion of catecholamines. 2. The perfused adrenal medulla was rich in vasoactive intestinal polypeptide (VIP) content (28 pmol g-1 of wet tissue). VIP-immunoreactive nerve fibres were present in the adrenal medulla and the adrenal cortex. 3. Field stimulation (10 Hz for 15 min plus 1 Hz for 15 min) caused a large increase in the output of VIP in the perfusate over the spontaneous release of VIP. Secretion of catecholamines was also greatly elevated by field stimulation. Field stimulation-evoked output of VIP and catecholamines was abolished after chronic denervation of the adrenal glands. 4. Infusion of acetylcholine (ACh) did not increase the output of VIP but caused a robust secretion of catecholamines. 5. The VIP output declined when the stimulation frequency was increased (8.6 x 10(-3) fmol pulse-1 at 1 Hz and 4.0 x 10(-3) fmol pulse-1 at 10 Hz). 6. In contrast, the output of 3H-acetylcholine (3H-ACh, expressed as a fraction of tissue 3H-ACh content) increased from 7.0 x 10(-2) pulse-1 at 1 Hz to 16.3 x 10(-2) pulse-1 at 10 Hz. 7. Secretion of catecholamines evoked by low-frequency stimulation (1 Hz) was reduced by 40% in the presence of cholinergic receptor antagonists (atropine plus hexamethonium). Inclusion of a VIP receptor antagonist ([Ac-Tyr1, D-Phe2]-GRF 1-29 amide) caused about 75% inhibition. 8. The VIP receptor antagonist inhibited VIP-evoked secretion of catecholamines without affecting ACh-evoked secretion. 9. In conclusion, VIP satisfies all the essential criteria to assume the role of a neurotransmitter in the rat adrenal medulla. The contribution of VIP to the secretion of adrenal medullary hormones is more prominent at low rates of neuronal activity whereas ACh is the major contributor at higher activity.

Depolarizing stimuli and neurotransmitters utilize separate pathways to activate protein kinase C in sympathetic neurons

Several types of extracellular signals affect the function of peripheral neurons. Depolarizing stimuli cause sudden increases in permeability to various ions leading to propagation of nerve impulses and release of transmitter substances. Neurons also receive external signals via neurotransmitter receptors located on the membrane. Different types of receptors present on sympathetic neurons are believed to modulate stimulation-evoked release of norepinephrine. We have investigated the effects of depolarizing stimuli and neurotransmitters on different signaling pathways in homogeneous cultures of chick sympathetic neurons. Depolarizing stimuli (35 mM KCl; electrical stimulation, 1 Hz for 5 min) and neurotransmitters (acetylcholine and 5-hydroxytrypatmine) enhanced membrane binding of protein kinase C by 2-5-fold. 35 mM KCl increased formation of 1,2-diacylglycerol and hydrolysis of [3H]phosphatidycholine without affecting [3H] phosphoinositide hydrolysis. Neurotransmitters increased [3H]inositol phosphates and 1,2-diacylglycerol without affecting the hydrolysis of [3H]phosphatidylcholine. 5-Hydroxytryptamine and acetylcholine (muscarinic component) did not increase Ca2+ concentration in the Indo-1-loaded neuronal cell body or the growth cone, but 35 mM KCl and electrical stimulation caused a marked increase in Ca2+ concentration in both regions of sympathetic neurons. We believe this to be the first demonstration of these two types of signalling mechanisms co-existing in sympathetic neurons; depolarization activate the phosphatidylcholine pathway and neurotransmitters activate the phosphatidylinositol pathway. The importance of two pathways in controlling neuronal Ca2+ concentration and the release of transmitter is discussed.

Phosphoinositide hydrolysis is not negatively regulated by protein kinase C in the peripheral tissues of rat and chick

1. Phorbol esters are known to inhibit phospholipase C-mediated hydrolysis of membrane phosphoinositide. This inhibition is attributed to participation of protein kinase C (PKC) in a negative-feedback control of phosphoinositide metabolism. We have tested this hypothesis by using different types of activators and inhibitors of PKC. 2. Phorbol-12,13-dibutyrate (PDB) inhibited the stimulatory effect of acetylcholine (ACh) on [3H]inositol monophosphate ([3H]IP) formation in cultured sympathetic neurons of the chick embryo and adrenal medulla of the rat. 3. Acetylcholine (ACh) and 5-hydroxytryptamine (5-HT) activated neuronal PKC by 3- to 8-fold. The extent of PKC activation by 100 microM-ACh was comparable to that of 100 nM-PDB. Activation of PKC by pre-incubation of sympathetic neurons with ACh (or 5-HT) did not inhibit the stimulatory effects of ACh (or 5-HT) on [3H]IP formation. 4. Pre-treatment of sympathetic neurons or adrenal medulla with a PKC inhibitor H7 (1-(5-isoquinolinyl-sulphonyl)-2-methyl-piperazine) almost completely blocked activation of the enzyme induced by PDB, ACh or 5-HT. However, blockade of PKC did not prevent the inhibitory effects of PDB on ACh-induced [3H]IP formation. 5. Vasoactive intestinal polypeptide (VIP) and muscarine induced catecholamine secretion from the perfused adrenal medulla via formation of inositol-1,4,5-tirisphosphate (IP3). Phorbol-12,13-dibutyrate decreased muscarine-induced catecholamine secretion. However, activation of PKC by VIP had no effect on muscarine-induced catecholamine secretion and vice versa. 6. These results suggest that PKC is not negatively coupled to phosphoinositide hydrolysis in sympathetic neurons and chromaffin cells. Phorbol esters must have targets other than PKC to interfere with the phosphoinositide hydrolysis.

Effects of neurotransmitters and peptides on phospholipid hydrolysis in sympathetic and sensory neurons

The effects of neurotransmitters and peptides on phosphoinositide hydrolysis were studied by measuring [3H]inositol monophosphate ([3H]IP) and protein kinase C (PKC) activity in the sympathetic and sensory neuronal cultures of the chick embryo. [3H]IP was increased in sympathetic neurons by acetylcholine (ACh), muscarine, serotonin (5-HT), and vasoactive intestinal polypeptide. ACh, muscarine, 5-HT, and bradykinin increased [3H]IP in sensory neuronal cultures. Dopamine, norepinephrine, histamine, and nerve growth factor did not stimulate [3H]IP formation in both cultures. ACh and phorbol 12,13-dibutyrate (PDB) increased the PKC activity by two- to sevenfold in the particulate fraction of both cultures. In sympathetic neurons, PKC activity was increased in the particulate fraction; activity in the cytosolic fraction was not affected. There was a 50% decline in the protein kinase C activity of the cytosolic fraction after PDB and ACh treatment of sensory cultures. The decline in PKC activity in the cytosolic fraction was attributed to the presence of nonneuronal cells in sensory cultures. To confirm this, the enzyme activity was determined in tissues that contain a heterogeneous population of cells. PDB activated PKC in the adrenal medulla and the brain of the rat. In both tissues there was a 65% decline in the PKC activity of the cytosolic fraction and about a 75% increase in the particulate fraction. We conclude that the mechanism of activation of protein kinase C in pure cultures of sympathetic neurons is different than in tissues containing a mixed population of neurons and nonneuronal cells.

Forskolin mediates the survival of nerve growth factor-dependent sympathetic neurons of chick embryo by a cyclic AMP-independent mechanism

Forskolin has become an invaluable tool for exploring the involvement of cyclic AMP in a variety of cellular functions. The diterpine directly activates the catalytic subunit of adenylate cyclase, causing a marked increase in cyclic AMP content. Because of this well-characterized action, practically all the observed effects of forskolin are commonly attributed to cyclic AMP-dependent processes. We show here that forskolin exerts a neurotrophic action that is almost identical to that of nerve growth factor (NGF) and phorbol 12,13-dibutyrate (PDB) but independent of cyclic AMP. Sympathetic neurons of the chick embryo supported in culture for 2 days by NGF, forskolin plus 3-isobutyl-1-methylxanthine (IBMX), or PDB had almost identical levels of cyclic AMP (between 9 and 12 pmol/mg protein). Neurons supported in culture for 2 days by NGF or PDB when challenged with forskolin plus IBMX showed almost a 15-fold increase in cyclic AMP, but those supported by forskolin plus IBMX and then exposed to the same combination of drugs did not show an increase in cyclic AMP, exhibiting a marked down-regulation. Exposure of neurons to forskolin for 2 h was ineffective in supporting long-term survival, suggesting that an initial increase in cyclic AMP formation is not sufficient but the continued presence of the drug is essential for survival. Effects of forskolin on the survival of these neurons could be observed even in the presence of dideoxyadenosine, and inhibitor of adenylate cyclase. Neurons supported by PDB for 2 days in culture when exposed to NGF for the first time did not show any increase in cyclic AMP, providing clear evidence that NGF does not affect this second messenger in its target cells. Similarly, neurons supported by NGF for 2 days when exposed to PDB did not show an increase in cyclic AMP.(ABSTRACT TRUNCATED AT 250 WORDS)

Veratrine supports the in vitro survival of embryonic chick sympathetic neurons

Veratrine (VT), an alkaloid known to act on the sodium channels and cause depolarization of a cell membrane, was found to support the survival of cultured sympathetic neurons. At 30 microM it was as effective as nerve growth factor (NGF), as determined by the cell counts and [3H]norepinephrine ([3H]NE) uptake. Protein kinase C (PKC) activity of the surviving neurons was measured because of our previous finding that depolarizing concentrations of K+ support the survival and cause several fold increase in the enzyme activity. An acute treatment of NGF-supported sympathetic neurons by VT did not alter PKC activity.

Survival of chick embryonic sensory neurons in culture is supported by phorbol esters

Sensory neurons of the chick embryo are supported in culture by several neurotrophic factors, including the phorbol esters. Because phorbol esters are known to activate one of the second messengers, namely, protein kinase C, it was of interest to see if the neurotrophic action of phorbol 12,13-dibutyrate (PDB) was related to the activation of protein kinase C in sensory neurons. Sensory neurons were obtained from dorsal root ganglia of 10-day-old chick embryos and maintained in a serum-free medium for several days to quantify survival and analyze protein kinase C activity. PDB (30 nM) supported the survival of approximately 50% of the total number of neurons plated. This value was comparable to that supported by nerve growth factor (NGF; 40 ng/ml). If PDB and NGF were added together, there was no additive effect on the survival. The protein kinase C activity of the particulate and cytosolic fractions of sensory neurons supported by NGF for 3 days was 1.26 +/- 0.1 and 2.9 +/- 0.32 pmol/min/mg of protein, respectively. In contrast, neurons supported by PDB showed an approximately 500% increase in enzyme activity in their particulate fraction. The enzyme activity of the cytosolic fraction was decreased by approximately 40%. If NGF-supported neurons were treated with PDB (30 nM) for 15 min, protein kinase C activity increased greater than 400% in the particulate fraction, whereas an approximately 50% decrease was observed in the cytosolic fraction. The protein kinase C value, expressed as a ratio of the activities in the particulate to cytosol fractions, showed large increases after phorbol treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiation induced blood pathology in chick-erythrocytes and related parameters

White leghorn male chicks at 15 days post-hatching were subjected to acute (2.10 Gy and 6.60 Gy) and fractionated (2 x 2.10 Gy) whole body gamma radiation exposure at the high dose rate of 0.60 Gy/sec to study the nature of haematological changes induced in the animals which were maintained for a maximum period of 60 days post irradiation. The investigated parameters include total red blood cell counts, haemoglobin content, haematocrit value, mean corpuscular volume and mean corpuscular haemoglobin concentration values. The results show that the haematological changes induced with 2.10 Gy and 2 x 2.10 Gy fractionated dosage are reversible and do not cause permanent damage to the erythroid characteristics. However, the system failed to recover with 6.60 Gy whole body acute exposure.

Haematocytometrical changes in chicken blood to acute 60Co gamma radiation

Newly hatched white leghorn chicks (Gallus domesticus) subjected to single whole body 2.25 Gy (225 rads) gamma radiation exposure at the dose rate of 0.50 Gy/sec (50 rads/sec), were studied for changes in a number of haematological parameters at days 1,3,5,7,14 and 28 post irradiation during development. The sudden decline and gradual recovery in total RBC and WBC counts and the level of Hb and Hct along with MCV, MCH and MCHC values evaluation indicates a high regenerative capability of leghorn chicks.

Cross-communication between acetylcholine and VIP in controlling catecholamine secretion by affecting cAMP, inositol triphosphate, protein kinase C, and calcium in rat adrenal medulla

The purpose of the present study was to determine the molecular mechanism of stimulatory actions of ACh and vasoactive intestinal polypeptide (VIP) by determining the role of various second messengers in the neurohumoral secretion. Toward such a goal, we measured cAMP, cGMP, protein kinase (PKC) activity, 3H-inositol triphosphate (3H-IP3), and 45Ca uptake in the adrenal medulla subjected to various treatments. Stimulation of splanchnic nerve endings increased 45Ca uptake, cAMP content, 3H-IP3, and PKC activity in the adrenal medulla. If muscarinic receptors of chromaffin cells were selectively activated by perfusion with muscarine, 3H-IP3 content and PKC activity were enhanced. Nicotine, on the other hand, increased only 45Ca uptake without affecting any other second messenger. Perfusion with VIP increased PKC activity and cAMP and 3H-IP3 content. None of the procedures affected cGMP content. Interplay among various second messengers was further investigated by studying interactions of nicotinic, muscarinic, and VIP-ergic receptors in modulation of catecholamine (CA) secretion and by using agents known to activate specific second messengers (e.g., forskolin, phorbol esters). Our results show that muscarine, VIP, and phorbol ester facilitated nicotine-evoked secretion by increasing PKC activity, and it was associated with an additional increase in 45Ca accumulation. On the other hand, secretion evoked by nicotine as well as muscarine was facilitated by forskolin without additional increase in 45Ca accumulation. A novel feature of the study is that ACh and VIP activate three types of receptors on chromaffin cells to stimulate and mutually facilitate the secretion of CA by generating various second messengers.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of denervation on loss of ions in chick skeletal muscle

Leaching behaviour of chick gastrocnemius muscle has been studied with respect to the loss of Na+, K+ and Ca2+ ions in a donor-solvent (muscle-water) system under normal as well as denervated conditions. An attempt has been made to explain the alterations in the rate of electrolytic loss in terms of membrane dysfunctions induced as a result of loss of neural control.

Alterations in phospholipid content of chick skeletal muscle under stress conditions

Alterations in the phospholipid levels of three gastrocnemii (G. externus, G. medius and G. internus) of chick have been studied during 56 days postembryonic growth of the three muscles. The effects of denervation and work-overload stress on their phospholipid content during the same period have been discussed in the light of denervation-induced membrane breakdown and exercise-induced fibre hypertrophy.

Ultrastructural demonstration of exocytosis in the intact rat adrenal medulla

Evidence is presented for morphological proof of exocytosis in the rat adrenal medulla in situ. Techniques were modified to allow perfusion of the intact adrenal gland with secretagogues (or electrical stimulation) followed by tannic acid. Unstimulated specimens demonstrated exocytotic (omega-shaped) profiles filled with flocculent material. This flocculation was also seen in the intercellular space. Stimulation of the adrenal medulla also resulted in the appearance of exocytotic profiles and an accumulation of the flocculent mass. This was often most evident in the subendothelial space. This is the first demonstration of exocytosis in the rat adrenal medulla by electron microscopy. The techniques used in this study will be useful for studying the pathway of secretory products of the adrenal chromaffin cell before they enter the vascular system.

Changes in leaching properties of chick skeletal muscles on denervation

The leaching of electrolytes in normal and denervated chick gastrocnemius muscle has been studied by recording electroconductivity changes in donor-solvent (muscle-water) system at 11 intervals leading to a total immersion of 5 hr 15 min, at days 1,5,10,21 and 28, post-hatching. The results show age related changes in the permeability properties of normal muscle membrane system. The loss of neural control induces a blocking of electrolytes 10 days post-denervation. The possible nature of blocking mechanism has been related to the non-availability of neuro-trophic factors in the tissue.

Glycogen accumulation in normal and irradiated minced muscle autografts on frog gastrocnemius

Alterations induced in glycogen content and phosphorylase activity have been studied in normal and irradiated minced muscle autografts on frog gastrocnemius at days 1, 3, 5, 7, 10, 15 and 30 postgrafting. The changes observed in the glycogen content and phosphorylase activity conform to the degeneration and regeneration phases of muscle repair. An attempt has been made to explain the altered glycogen utilizing capacities of the frog skeletal muscle during its repair and regeneration.

Demonstration of adrenergic and dopaminergic receptors in cultured sympathetic neurons--their coupling to cAMP but not to the transmitter release process

Experiments were carried out on cultured sympathetic neurons of the chick embryo; first, to demonstrate the presence of adrenergic and dopaminergic receptors, and then to see if these receptors are involved in regulation of transmitter release. We show that alpha 2-agonists, norepinephrine, epinephrine and clonidine, had no effect on neuronal cyclic 3',5'-adenosine monophosphate content. Forskolin enhanced neuronal cyclic 3',5'-adenosine monophosphate from a control value of about 20 pmoles/mg protein to 150 pmoles/mg protein. In the presence of alpha 2-agonists and forskolin the cyclic 3,5'-adenosine monophosphate content increased between 340 and 430 pmoles/mg protein. The alpha 1-agonist, phenylephrine, had no such effect. The facilitatory effect of alpha 2-agonist on forskolin-stimulated cyclic 3',5'-adenosine monophosphate production was blocked by the alpha 2-antagonist, yohimbine, but not the alpha 1-agonist, prazosin. Dopamine did not affect neuronal cyclic 3',5'-adenosine monophosphate content, but forskolin-stimulated increase in cyclic 3',5'-adenosine monophosphate was further facilitated by dopamine, and this effect was blocked by haloperidol. Activation of neuronal alpha 2-receptors by norepinephrine, epinephrine and clonidine did not interfere with electrically induced release of tritium from [3H]-norepinephrine-loaded sympathetic neurons. However, if sympathetic neurons were co-cultured with heart cells, clonidine, norepinephrine and epinephrine markedly inhibited the stimulation-induced release. Yohimbine or phentolamine partially reversed the inhibitory effects of alpha 2-agonists. alpha 2-Agonists and -antagonists also modified stimulation-induced release of tritium from [3H]norepinephrine-loaded hearts of the chick embryo.(ABSTRACT TRUNCATED AT 250 WORDS)

Excess K+ and phorbol ester activate protein kinase C and support the survival of chick sympathetic neurons in culture

The effects of phorbol esters were investigated on the survival of chick sympathetic neurons in a serum-free culture medium. The protein kinase C activator phorbol 12,13-dibutyrate (PDB) supported about 40% of the plated sympathetic neurons. This number was comparable to that supported by nerve growth factor (NGF). A combination of phorbol ester and NGF did not significantly increase the number of surviving neurons. Phorbol ester-supported sympathetic neurons possessed desipramine-sensitive [3H]-norepinephrine uptake mechanism, and therefore were noradrenegic in character. Two days after the start of cultures, if NGF was replaced by phorbol ester, or phorbol ester was replaced by NGF, the number of surviving sympathetic neurons was essentially the same in both groups, and the uptake of [3H]norepinephrine was also comparable when examined 2 days after the switchover. Interchangeability between phorbol ester and NGF in the survival of sympathetic neurons suggests that both agents act on the same subpopulation of neurons of the chick sympathetic ganglia. The protein kinase C activity of cytosol and particulate fractions of NGF-supported neurons was 0.14 and 0.09 pmol/min/mg protein, respectively. In phorbol ester-supported neurons the activity in the particulate fraction increased by about fivefold. Removal of the phorbol ester after 2 days resulted in restoration of the enzyme activity in less than 1 h, and readdition of the phorbol ester again increased the activity by fivefold. When NGF was added to these neurons (1 microgram for 15 min), there was no change in the enzyme activity. Phorbol 13-acetate was ineffective in supporting sympathetic neurons in culture, as well as in enhancing protein kinase C activity. We also compared the protein kinase C activity of sympathetic neurons supported in culture by NGF and excess potassium (35 mM K+) Neurons supported in culture by 35 mM K+ for 2 days had almost eightfold more protein kinase C activity in their particulate fraction than in cytosol fraction. In NGF-supported neurons were acutely treated with excess K+, the protein kinase C activity was increased in the particulate fraction by about sevenfold in a concentration- and time-dependent manner. Excess K+ plus phorbol ester did not produce an additive effect on protein kinase C activity. PDB and excess K+ had no effect on cyclic AMP content of sympathetic neurons. In summary, the present data suggest that the neurotrophic action of PDB and excess K+ is probably mediated through protein kinase C.