Fermentor temperature as a tool for control of high-density perfusion cultures of mammalian cells

Temperature is a key environmental variable whose potential in animal cell fermentor optimization is not yet fully utilized. The scarce literature data suggests that reduced fermentor temperature results in an improved viability and shear resistance, higher cell density and titer in batch cultures, and reduction in glucose/lactate metabolism. Due to the arrest of the cells in the G1 phase, the specific growth rate was found to decrease at temperatures below 37.0 degrees C. The response of the specific production rate was cell line dependent: in some cases it increased 2-to-3-fold, but decreased in other cases. The controlable slowdown of cell metabolism at lower temperature can be used in optimization of perfusion mammalian cell cultures with several potential advantages, including higher cell density in oxygen limited reactors, lower perfusion rate, improved product quality, simplified pH control, and others. To evaluate this strategy, a series of long-term experiments in 15 L perfusion bioreactors culturing recombinant hamster cells at 20.0 x 10(6) cells/mL were conducted. The temperature was changed over a range of set points, and maintained at each of these for a long period of time. Steady state process data was collected and analyzed. The effect of temperature on the following characteristics of the perfusion process was studied: cell growth, glucose/lactate metabolism, glutamine/ammonia metabolism, cell respiration, cell density at constant oxygen transfer rate, proteolytic activity, and product quality (glycosylation and molecule fragmentation). The results suggest that temperature is a variable with a significant potential in optimization of perfusion cultures. Properly selected temperature set point will contribute to the overall improvement of process performance. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 328-338, 1997.

Twin to twin transfusion syndrome

Twin to twin transfusion syndrome (TTTS) is a specific condition complicating 10-15% of monochorionic multiple pregnancy. Intertwin vascular anastomoses and transfusion is a normal event. Syndrome develops when blood flow is unbalanced. Recent studies suggest a paucity of bi-directional superficial anastomoses failing to compensate for hemodynamic imbalance resulting from unidirectional transfusion along deeper arterio-venous anastomoses. TTTS is associated with high rates of perinatal mortality. Acute and chronic forms exist and severity varies. The donor twin is often smaller, hypovolemic, anemic and develops congestive heart failure. The recipient is usually heavier and polycythemic. Antenatally, second trimester ultrasound usually detects the condition. Serial amnioreduction is the recommended therapy. Postnatally, intertwin haemoglobin and birth weight differences along with pallor in one twin and plethora in the other are helpful in making a diagnosis. Medical care of twins after birth is directed towards problem related to anemia, polycythemia and hydrops. Review of the syndrome is presented with an illustrative case.

Pharmacotherapy for meconium aspiration

In this article we have attempted to review the current pharmacological treatment options for infants with meconium aspiration syndrome with or without persistent pulmonary hypertension. These treatments include ventilatory support, surfactant treatment and inhaled nitric oxide (INO), in addition to older and newer pharmacological treatments. These include sedatives, muscle relaxants, alkali infusion, antibiotics and the newer vasodilators. Many aspects of treatment, including ventilatory care, surfactant treatment and the use of INO, are reviewed in great detail in this issue. On the other hand, many newer pharmacological modalities of treatment described here have not been evaluated with randomized control trials. We have given an overview of these emerging therapies.

Stent graft exclusion of pseudo-aneurysm arising from PTFE hemodialysis graft after recurrence following ultrasound guided thrombin injection

There are various non-invasive or minimally invasive techniques for management of pseudoaneurysms including ultrasound guided compression, ultrasound guided thrombin injection and covered stent placement. We report a case where a covered stent graft was successfully used for the treatment of a pseudoaneurysm directly arising from a PTFE graft which recurred 3 months following treatment with ultrasound guided thrombin injection.

Endovascular repair of a ruptured mycotic aneurysm of the common iliac artery

This report describes the case of a ruptured mycotic aneurysm of the left common iliac artery, successfully treated with endovascular stent-grafting. A 64-year-old woman underwent diagnostic coronary angiography complicated by an infected hematoma of the left groin. Seven days later, she developed methicillin-resistant Staphylococcus aureus septicemia and CT scan evidence of perivascular inflammation around the left common iliac artery. This was followed by rupture of a mycotic aneurysm of the left common iliac artery. The lesion was successfully treated with a stent-graft and prolonged antibiotic therapy, and the patient remains free of infection 10 months later. Accumulating evidence suggests that endovascular repair can be used safely for the repair of ruptured infected aneurysms.

Effect of pioglitazone therapy in lean type 1 diabetes mellitus

OBJECTIVE

The beneficial effects of metformin in peripubertal adolescents and rosiglitazone in overweight type 1 diabetic subjects, though modest have been demonstrated. This study was designed to analyze the effect of pioglitazone as an adjunctive therapy in post-pubertal lean T1DM.

PATIENTS AND METHODS

Sixty type 1 diabetic subjects with duration of illness of a year or more with body mass index between 18 and 24.9 kg/m(2) were randomly assigned to receive either 30 mg pioglitazone or placebo once daily for 6 months. The study was double-blinded placebo controlled with 30 subjects in each group, matched for age, sex, anthropometric and metabolic parameters. At the end of the study period, plasma glucose levels, HbA(1c), lipids and insulin requirement were compared between the two groups.

RESULTS

A significant improvement in post-prandial plasma glucose (PPPG) levels (9.1+/-1.7 and 8.4+/-1.3 mmol/L, p=0.002) and HbA(1c) (7.08+/-0.48 and 6.86+/-0.45%, p=0.001) were observed in the pioglitazone treated group, but not in the placebo treated group (8.3+/-1.8 and 7.8+/-1.8 mmol/L, p=0.06 and HbA(1c) 7.3+/-0.37 and 7.24+/-0.33%, p=0.74, respectively). However, the mean decrease in PPPG and HbA(1c) levels between groups corrected for baseline values at the end of study was significant only for the later (HbA(1c) -0.22+/-0.29 and -0.06+/-0.49, p=0.03), while for the former, it got attenuated (PPPG -0.69+/-1.1 and -0.48+/-1.36, p=0.68). There was no alteration in body weight, body mass index, insulin requirement, blood pressure and lipid profile in both the groups at the end of the study.

CONCLUSION

Pioglitazone is modestly effective adjunct to insulin therapy in lean type 1 diabetic subjects. It improves post-prandial glucose levels and HbA(1c) without alterations in body weight and insulin requirement.

Accidental blood exposure: risk and prevention in interventional radiology

There is a growing concern about the transmission of bloodborne pathogens during medical procedures among health care workers and patients. Over the last three decades, radiological services have undergone many changes with the introduction of new modalities. One of these new disciplines is interventional radiology (IR) which deals with procedures such as arteriography, image-guided biopsies, intravascular catheter insertions, angioplasty and stent placements. Despite these developments, the potential for accidental blood exposure and exposure to other infectious material continues to exist. Therefore, it is important for all radiologists who perform invasive procedures to observe specific recommendations for infection control. In this review, we look at the different policies for protection and universal standards on infection control.

Precocious pseudopuberty with testicular enlargement

Gonadotropins independent precocious puberty (GIPP) in male is characterized by early appearance of sexual hairs and phallic growth but without testicular enlargement. We report a case of GIPP with testicular enlargement who was diagnosed to have testotoxicosis and successfully managed with spironolactone.

Ichthyosis follicularis, alopecia and photophobia (IFAP) syndrome treated with acitretin

We describe a 3-year-old male patient with the ichthyosis follicularis, alopecia and photophobia (IFAP) syndrome, who developed cutaneous and ocular involvement in infancy. In addition, he had growth retardation and borderline intelligence; no other systemic involvement was found on detailed investigation. A moderate response to acitretin therapy (1 mg/kg) administered for 6 months was observed, with improvement in cutaneous features and corneal erosions and no change in alopecia or photophobia.

Diminished lung function, RSV infection, and respiratory morbidity in prematurely born infants

BACKGROUND

Diminished lung function appears to be a risk factor for respiratory syncytial virus (RSV) infection/bronchiolitis in term born infants.

AIMS

To determine if diminished lung function prior to neonatal unit discharge was associated with subsequent symptomatic RSV lower respiratory tract infection (LRTI) and respiratory morbidity in prematurely born infants.

METHODS

Of 39 infants in a tertiary neonatal intensive care unit (median gestational age 28 weeks, range 23-31), 20 had bronchopulmonary dysplasia. Lung function (compliance and resistance of the respiratory system (C(rs) and R(rs)) and functional residual capacity (FRC)) was measured on the neonatal unit at 36 weeks postmenstrual age (PMA). Following neonatal unit discharge, nasopharyngeal aspirates were obtained on every occasion, at home or in hospital, an infant had an LRTI. RSV was identified by immunofluorescence and/or culture.

RESULTS

The 15 infants who suffered a symptomatic RSV LRTI had a higher mean R(rs) and suffered more wheeze at follow up than the rest of the cohort. Regression analysis showed that a high R(rs) was significantly associated with a symptomatic RSV LRTI; significant factors for cough were a high R(rs) and a symptomatic RSV LRTI, and for wheeze were a high R(rs).

CONCLUSION

Prematurely born infants, who had a symptomatic RSV LRTI and/or respiratory morbidity at follow up, had worse lung function prior to neonatal unit discharge.

Characterization of serine/cysteine protease inhibitor α1-antitripsin from meconium-instilled rabbit lungs

We have recently purified from meconium-instilled rabbit lungs a novel serine proteinase inhibitor, with an apparent molecular mass of 50 kDa, which we assign to be alpha1-antitripsin. We hypothesize that serpin may attenuate pulmonary inflammation and improve surfactant function after meconium aspiration. Alpha1-antitripsin is a member of the proteinase inhibitor (serpin) superfamily and inhibitor of neutrophil elastase, and it can be identified as a member of the family by its amino acid sequence due to the high degree of conserved residues. Alpha1-antitripsin is synthesized by epithelial cells, macrophages, monocytes, and neutrophils. Deficiency in alpha1-antitripsin leads to exposure of lungs to uncontrolled proteolytic attack from neutrophil elastase or other damaging factors culminating in lung destruction and cell apoptosis. We hypothesize that accumulation of alpha1-antitripsin in the lungs serves as a predisposed protection against meconium-induced lung injury. In this paper, we show how this knowledge can lead to the development of novel therapeutic approaches for treatment of MAS.

GSK-3beta inhibition reverses axonal transport defects and behavioural phenotypes in Drosophila

The tauopathies are a group of disorders characterised by aggregation of the microtubule-associated protein tau and include Alzheimer's disease (AD) and the fronto-temporal dementias (FTD). We have used Drosophila to analyse how tau abnormalities cause neurodegeneration. By selectively co-expressing wild-type human tau (0N3R isoform) and a GFP vesicle marker in motorneurons, we examined the consequences of tau overexpression on axonal transport in vivo. The results show that overexpression of tau disrupts axonal transport causing vesicle aggregation and this is associated with loss of locomotor function. All these effects occur without neuron death. Co-expression of constitutively active glycogen-synthase kinase-3beta (GSK-3beta) enhances and two GSK-3beta inhibitors, lithium and AR-A014418, reverse both the axon transport and locomotor phenotypes, suggesting that the pathological effects of tau are phosphorylation dependent. These data show that tau abnormalities significantly disrupt neuronal function, in a phosphorylation-dependent manner, before the classical pathological hallmarks are evident and also suggest that the inhibition of GSK-3beta might have potential therapeutic benefits in tauopathies.

Cocaine permeability and metabolism in colonic T-84 epithelial cell line

We studied the uptake, transport and metabolism of cocaine in human intestine using the colonic T-84 monolayers as a model. T-84 cells were grown in DMEM/Ham's F-12 medium containing 6% newborn calf serum at 37 degrees C on 1.0 microm collagen inserts. The cells develop into a polarized monolayer with the apical surface facing the upper chamber and the basolateral surface facing the lower. The monolayers develop a transepithelial resistance of > or = 600 ohms cm2 in 7 days. Varying concentrations of cocaine HCI was added in a serum free medium to the luminal side only, and after 30 min and 60 min samples from the luminal and serosal aspect were removed for analysis. Cocaine and its metabolites were measured by GC/MS. Cocaine transport across T-84 monolayers increased linearly with increasing concentration of cocaine, with no significant difference between 30 min and 60 min of exposure. Transepithelial resistance did not change even at 800 ng of cocaine suggesting no effect on monolayer viability. The metabolites, benzoylecgonine (BE) and ecgonine methyl ester (EME) but not norcocaine were detected in both luminal and serosal side. The concentrations of BE and EME in the luminal side were significantly higher than in the serosal. Combined recovery of cocaine, BE and EME from luminal and serosal sides were 52 - 80% of total added cocaine. While fresh medium did not metabolize cocaine, media previously exposed to the monolayer (cell-free medium) caused a significant breakdown into BE and EME, suggesting that esterases may be released into the medium. These results indicate transfer of cocaine across this model of intestinal epithelial cell line is by simple diffusion and is concentration dependent. These studies imply that cocaine in swallowed amniotic fluid can be absorbed by the fetal gastrointestinal tract.

Effect of pH on stability of anthrax lethal factor: correlation between denaturation and activity

Anthrax is caused by Gram positive bacterium Bacillus anthracis. Pathogenesis is result of production of three protein components, protective antigen (PA), lethal factor (LF), and edema factor (EF). PA in combination with LF (lethal toxin) is lethal to animals, while PA in combination with EF (edema toxin), causes edema. PA, LF, and EF are very thermolabile. Differential scanning calorimetry (DSC) was used to unravel the energetics of LF denaturation as a function of pH ranging from 7.8 to 5.5. Transition temperature (T(m)) of LF was found to be approximately equal to 42 degrees C and onset of denaturation occurs at approximately equal to 30 degrees C. The ratio of calorimetric to van't Hoff's enthalpy was nearly equal to unity at pH 7.0, indicative of presence of single structural domain in LF at pH 7.0, unlike PA which has been structurally observed to consist of 4 domains. It was found by cytotoxicity studies using J774A.1 macrophage like cells that LF was most stable at pH approximately 6.5. This paper reports for the first time the denaturation of LF at different pH values at 37 degrees C and tries to establish a correlation between denaturation and loss of LF activity at different pH values.

Regulation of metallothionein II messenger ribonucleic acid measures exogenous estrogen receptor-beta activity in SAOS-2 and LNCaPLN3 cells

Estrogen receptor-beta (ERbeta) is a recently discovered member of the steroid hormone superfamily. Because its distribution is distinct from that of the classical estrogen receptor, and it is expressed in several nonclassical estrogen target tissues (e.g. prostate and bladder), its role in mediating the action of estrogen is unclear. One approach to elucidating the function of this receptor is to identify genes that it regulates. Using differential display, we profiled the messenger RNAs regulated by 17beta-estradiol in SAOS-2 and LNCaPLN3 cells overexpressing ERbeta. Follow-up studies used cells expressing either ERalpha or ERbeta. One gene, metallothionein II, was regulated by both receptor subtypes in LNCaPLN3 cells, but only by ERbeta in SAOS-2 cells. Because cycloheximide blocks this response, induction is probably mediated through regulation of at least one other protein. Identification of endogenous genes that are regulated differentially by ERalpha and ERbeta will be valuable tools in elucidating the function of ERbeta and the mechanisms by which these two receptors regulate transcription.