Guinea pig mast cells: comparative study on morphology, fixation and staining properties

We have studied the distribution of mast cells (MC) in different tissues of the guinea pig (GP), and certain aspects of their histochemical and cytochemical properties. In preparations fixed with Carnoy's fluid, MC were extremely well-preserved and were detected in all tissue sections and cytocentrifuge smears obtained from enzymically dispersed cells after staining with alcian blue at pH 0.5-2.2. In formol-saline-fixed preparations, there was a substantial reduction in MC counts. Most of the tissue MC were located interstitially and in the perivascular connective tissue. A small proportion of MC was located in certain organ- or tissue-specific structures. When counted manually, MC comprised 0.43-3.1% of the cell population obtained by enzymic dispersion. This proportion was higher than that obtained by the automated Technicon H6000 basophil system, but the two counting systems confirmed organ differences in MC counts. MC in different GP tissues varied in size, morphology, histamine content and degree of susceptibility to formol-saline fixation. The granules of GP connective tissue MC differed from those of rat peritoneum in failing to take the fluorescent stain berberine sulphate which has greater affinity for the highly sulphated glycosaminoglycans such as heparin, and in having some morphological and histochemical similarity to 'mucosal' MC.     

The relationship of preoperative distress to endocrine and subjective responses to surgery: Support for Janis' theory

To test Janis' theory that preoperative worry can improve postoperative recovery, endocrine and subjective responses were measured in 27 patients undergoing major abdominal surgery which entailed threat to their health or longevity. Questionnaires to assess emotional and somatic state were completed preoperatively and for 7 days postoperatively. Plasma cortisol, noradrenaline, adrenaline, and glucose were measured pre-, per-, and postoperatively. Preoperatively, noradrenaline correlated positively with pain and distress, and adrenaline negatively. Postoperatively, endocrine levels and distress were not clearly related. Nevertheless, preoperative pain negatively correlated with postoperative adrenaline and cortisol levels. This, and the negative correlation between preoperative distress and postoperative pain are consistent with Janis' theory. In addition, we found that the longer patients waited on the day of surgery, the greater were the cortisol, noradrenaline, and glucose responses.     

Doppler ultrasound of the uteroplacental circulation as a screening test for severe pre-eclampsia with intra-uterine growth retardation

Two hundred primiparae underwent continuous-wave Doppler investigation of the uteroplacental circulation at 18-20 weeks gestation as a possible screening test for hypertension in pregnancy. Seventy-five women with abnormal waveforms suggestive of high uteroplacental resistance were tested again at 24 weeks when 21 demonstrated a persistent abnormality. Only nine (43%) of these went on to have an uncomplicated pregnancy, as compared with 150 (84%) of the remainder. Seventeen (8.5%) of the women in the study developed a hypertensive disorder of pregnancy, five of whom had abnormal waveforms at 18-20 weeks and at 24 weeks. These five women had a more severe degree of hypertension with proteinuria or intra-uterine growth retardation, and two required clinical intervention before term. The remaining 12 women were delivered at term of average, or heavier than average babies. Doppler investigation of the uteroplacental circulation at 24 weeks may prove to be a sensitive screening test for later severe pre-eclampsia with intra-uterine growth retardation.     

Isolation and characterisation of T lymphocytes from the urethra of patients with acute urethritis [published erratum appears in Sex Transm Infect 1998 Dec;74(6):459]

OBJECTIVES: To investigate local cellular immune responses in patients with acute urethritis. METHODS: We have established T cell lines from the urethral exudate and examined their phenotype by flow cytometry. As controls, T cell lines were cultured from first pass urine specimens of asymptomatic healthy individuals. RESULTS: Using interleukin 2 (IL-2) alone a T cell line was obtained on only one occasion. Following culture with IL-2, and subsequent expansion by a single stimulation with irradiated allogenic peripheral blood mononuclear cells (PBMC), phytohaemagglutinin (PHA), and IL-2, it was possible to establish T cell lines from 6/6 acute urethritis patients. T cell lines were also obtained from 4/12 controls subjects, but required repetitive rounds of stimulation with mitogen and allogeneic PBMC to produce sufficient cell numbers for analysis. Three of the patient T cell lines were dominated by T cells expressing the gamma delta receptor. CONCLUSION: The gamma delta T cell subset has been associated with immune responses at mucosal surfaces and has the ability to recognise certain bacterial antigens. The gamma delta T cell response may represent an important aspect of the immune response to organisms associated with acute urethritis.


     

Interactions of theβ carboline abecarnil with the high pressure neurological syndrome in a primate model

The neurophysiological interactions between the high pressure neurological syndrome (HPNS) and a new carboline, abecarnil, were studied in the nonhuman primatePapio anubis. Abecarnil is a partial agonist at the benzodiazepine site on the GABA/benzodiazepine receptor. Six animals were exposed on two occasions to pressures of 91 ATA in an environment of helium and oxygen. One exposure was pretreated with a total dose of abecarnil 1.0 mg/kg, the other with an equivalent volume of vehicle. Treatment with abecarnil prevented the severe signs of HPNS occurring between 51 and 91 ATA. Onset pressures of the various signs were unaffected. Some signs, e.g. myoclonus, became more frequent when abecarnil was used. A residual protective effect of abecarnil was present 4 weeks after the dose was given, active at pressures less than 71 ATA. Changes with pressure in the EEG were recorded primarily from the frontal cortex, but were also present in the parietal and occipital areas of the left cortex. Amplitude and frequency spectra were calculated and changes with pressure in the four conventional wavebands, plus two others, analysed. The most striking change was the prevention by abecarnil of the pressure-induced 100% increase in alpha wave amplitude in the frontal region. It is concluded that modulation of GABA transmission is important in controlling the expression of HPNS.     

Metabolic Response of Triple-Negative Breast Cancer to Folate Restriction

Background: Triple-negative breast cancers (TNBCs), accounting for approximately 15% of breast cancers, lack targeted therapy. A hallmark of cancer is metabolic reprogramming, with one-carbon metabolism essential to many processes altered in tumor cells, including nucleotide biosynthesis and antioxidant defenses. We reported that folate deficiency via folic acid (FA) withdrawal in several TNBC cell lines results in heterogenous effects on cell growth, metabolic reprogramming, and mitochondrial impairment. To elucidate underlying drivers of TNBC sensitivity to folate stress, we characterized in vivo and in vitro responses to FA restriction in two TNBC models differing in metastatic potential and innate mitochondrial dysfunction. Methods: Metastatic MDA-MB-231 cells (high mitochondrial dysfunction) and nonmetastatic M-Wnt cells (low mitochondrial dysfunction) were orthotopically injected into mice fed diets with either 2 ppm FA (control), 0 ppm FA, or 12 ppm FA (supplementation; in MDA-MB-231 only). Tumor growth, metabolomics, and metabolic gene expression were assessed. MDA-MB-231 and M-Wnt cells were also grown in media with 0 or 2.2 µM FA; metabolic alterations were assessed by extracellular flux analysis, flow cytometry, and qPCR. Results: Relative to control, dietary FA restriction decreased MDA-MB-231 tumor weight and volume, while FA supplementation minimally increased MDA-MB-231 tumor weight. Metabolic studies in vivo and in vitro using MDA-MB-231 cells showed FA restriction remodeled one-carbon metabolism, nucleotide biosynthesis, and glucose metabolism. In contrast to findings in the MDA-MB-231 model, FA restriction in the M-Wnt model, relative to control, led to accelerated tumor growth, minimal metabolic changes, and modest mitochondrial dysfunction. Increased mitochondrial dysfunction in M-Wnt cells, induced via chloramphenicol, significantly enhanced responsiveness to the cytotoxic effects of FA restriction. Conclusions: Given the lack of targeted treatment options for TNBC, uncovering metabolic vulnerabilities that can be exploited as therapeutic targets is an important goal. Our findings suggest that a major driver of TNBC sensitivity to folate restriction is a high innate level of mitochondrial dysfunction, which can increase dependence on one-carbon metabolism. Thus, folate deprivation or antifolate therapy for TNBCs with metabolic inflexibility due to their elevated levels of mitochondrial dysfunction may represent a novel precision-medicine strategy.