Recurrent miscarriage associated with antiphospholipid antibodies: prophylactic treatment with low-dose aspirin and fish oil derivates

PROBLEM

The aim of this study was to evaluate the effects of two different prophylactic protocols, low-dose aspirin and fish oil derivates, in the treatment of patients with recurrent pregnancy loss associated with antiphospholipid antibodies (APA) syndrome.

METHODS

A prospective study included 30 patients who were alternately assigned to treatment. Each patient had had at least two consecutive spontaneous abortions, positive antiphospholipid antibodies on two occasions, and a complete evaluation.

RESULTS

Among patients treated with low-dose aspirin, 12 out of the 15 (80%) pregnancies ended in live births. In the fish oil derivate group 11 out of the 15 (73.3%) ended in live births (p > 0.05). There were no significant differences between the low-dose aspirin and the fish oil derivates groups with respect to gestational age at delivery (39.9 +/- 0.4 vs 39 +/- 1.5 weeks), fetal birth weight (3290 +/- 200g vs 3560 +/- 100 g), number of cesarean sections (25% vs 18%), or complications.

CONCLUSION

There were no significant differences in terms of pregnancy outcome between women with recurrent pregnancy loss associated with APA syndrome treated with low-dose aspirin or fish oil derivates.

Periodontal disease and poor obstetrical outcome

Maternal infective processes sustained especially by Gram-negative anaerobic bacteria like periodontal disease, during pregnancy, have been demonstrated to perturb the physiologic course of parturition through inflammatory cytokine production, sometimes resulting in preterm labor, preterm premature rupture of membranes and preterm low birth weight. In a matched case-control study, the hypothesis that poor oral health of pregnant women is a risk factor for low birth weight (LBW) was evaluated. Gingival crevicular fluid levels of PGE2 and IL-1beta were measured in order to determine whether mediator levels were related to current pregnancy outcome. Results indicate that GCF-PGE2 and GCF-IL-1beta levels are significantly higher in preterm low birth weight (PLBW) mothers as compared with normal birth weight controls. The data confirm that there is a possible correlation between periodontal problems typical of pregnancy and the occurrence of complications such as preterm low birth weight.

Postoperative adhesion prevention in gynecologic surgery with hyaluronic acid

Despite improvements in surgical instrumentation and techniques, adhesions continue to form after most procedures. Peritoneal adhesions develop in 60-90% of women who undergo major gynecological operations. This adhesion formation causes significant postoperative morbidity such as bowel obstruction (65%), infertility (15-20%), and chronic pelvic pain (40%).

OBJECTIVE

To demonstrate the efficacy of a hyaluronic acid product (Hyalobarrier Gel) for the prevention of adhesions in gynecological surgery.

MATERIALS AND METHODS

From October 2000 to July 2002, 18 women from 26 to 41 years old (mean age 33.66) underwent myomectomy via laparotomy as their first abdominal operation. Between August 2001 and May 2003, the patients underwent a second-look laparoscopy (7 women, 38.9%, 15 sites, 42.8%) or a second-look laparotomy (11 women, 61.1%, 20 sites, 57.1%) during which all the 35 sites corresponding to the previous myomectomies were analyzed. During the second-look procedure the presence, localization and severity of adhesions were evaluated using the Operative Laparoscopy Study Group Classification (OLSG) and American Fertility Society Classification (AFSC).

RESULTS

All patients underwent a second-look laparoscopy/laparotomy and only five of 18 (27.7%) showed pelvic adhesions in seven sites (20%) of previous myomectomies. No adhesion was found on the previous sites of myomectomies of pedunculated leiomyomas so, excluding those, adhesions were found in seven of 29 sites of myomectomies (24.1%).

CONCLUSIONS

The present study emphasizes the need for improved treatments to prevent adhesions, as there is no doubt that adhesions represent one of the major causes of female morbidity.

The adolescent and the gynecologist: our experience

To evaluate adolescents' knowledge about sex, we conducted a study divided in two parts: 1) Distribution of a questionnaire; 2) Impromptu conversation with adolescents. The sample consisted of 205 questionnaires and 115 talks with students at a high school. The gathered data let us deduce that the relationship with parents was regarded as pleasant and good. As was expected the whole emotional sphere was related to friends. In order to understand which structures can help adolescents our data revealed that the mother holds first place, followed by the school and by friends. Sex education during adolescence should be carried out by other institutions so that a relationship free from conflicts can be established. In this way the figure of the expert takes shape--someone who can communicate within the structure of the school and the family and beyond--the limits of the information given by friends.

Tension-free vaginal tape procedure for treatment of USI: subjective and objective efficacy evaluation

Urinary incontinence is a frequent functional disease affecting 5% to 25% of women. It is commonly believed that urinary stress incontinence (USI) is caused by anatomical defects, thus it can be treated by restoring anatomy. More than 100 surgical techniques have been proposed for genuine stress incontinence treatment. The tension free vaginal tape procedure (TVT) for the treatment of genuine IUS in women was first reported in 1996 by Ulmsten et al. The purpose of this study was to evaluate objective and subjective efficacy of the TVT procedure in different types of female urinary incontinence. From February 2000 to December 2001, 52 patients with urinary incontinence underwent the TVT procedure in the Obstetric and Gynecology Department of Avezzano Hospital, Italy. No difference in the cure rates was found between patients undergoing the TVT alone or associated with anterior and/or posterior colporrhaphy. In accordance with many authors we can affirm that the TVT sling technique is easy to use, the time for surgery is relatively short, and the procedure is free of complications and provides a satisfactory outcome.

Disturbances of humour in postpartum: our experience

The study was conducted on 64 women who were to give birth. The average age ranged from 31-44 years and the instruments for evaluation consisted of: 1) Individual and psychological questionnaires; 2) Italian version of the Short Form Health Survey Questionnaire (SF-36); 3) Sheehan Disability Scale; 4) Zung self-rating depression scale. Of the women included in the study 27.7% found their humour worsened during their last pregnancy, while 19.15% said that their humour worsened after the birth. In these patients we frequently found obstetric and/or puerperal pathologies. There was also a strong correlation with the premenstrual syndrome and with hyperemesis in the first trimester. On the contrary, there was no correlation with familiarity and socio-demographic characteristics. The data allow us to conclude that any pregnant woman can develop medium or strong symptoms of depression thus calling for great attention to be paid to the psychological dynamics of birth.

[Diagnostic hysteroscopy in the third millennium. Indications and role]

BACKGROUND

The present paper analyses a recent personal series of 284 diagnostic hysteroscopies carried out between May 1999 and December 2001 at the Operating Unit of the University Gynaecology and Obstetrics Department of the Hospital of Avezzano. Emphasis is laid on the description of the indications underlying the investigation and on the hysteroscopic and histological findings in the cases examined.

METHODS

The sample was also subdivided into two groups depending on the fertility or postmenopausal status of the patients. In the sample of 284, 89 (31.3%) patients were subjected to local anaesthesia with paracervical block, while the remaining 195 (68.7%) did not receive any form of anaestetic. The hysteroscopies were generally carried out in day surgery, using the commonest and most tried and tested hysteroscopic optic systems and carbon dioxide as a means for distending the uterine cavity. None of the hysteroscopies gave rise to important complications.

RESULTS

In both the group of patients in fertile age and in the group of post-menopause patients, the main indication for hysteroscopy was anomalous uterine bleeding (AUB) for which a total of 159/284 hysteroscopies (56%) were carried out, of which 68 (42.8%) in patients in fertile age and 91 (57.2%) in post-menopause patients. In the group of post-menopause patients hysteroscopy was carried out for this indication in 73.4% of cases (91/124) while in fertile age it was performed in 42.5% of cases (68/160).

CONCLUSIONS

Underlying AUB in the post-menopause patient endometrial hypo-atrophy was evidenced in 59 of 91 patients examined (64.9%), while in fertile age most of the 68 cases of AUB proved to be of dysfunctional nature: hystological examination showed a proliferative endometrium in 29 cases, secretory in 7 and hyperplastic in 12 cases (11 cases of simple endometrial hyperplasia with atypia and 1 of complex hyperplasia with atypia). Finally, hysteroscopy made it possible to diagnose 6 cases of endometrial adenocarcinoma (6.6% of patients with AUB in post-menopause).

Vaccenic acid feeding increases tissue levels of conjugated linoleic acid and suppresses development of premalignant lesions in rat mammary gland

The objective of this report was to determine whether vaccenic acid (t11-18:1) is converted efficiently to conjugated linoleic acid (c9,t11-18:2, CLA) in rats via the delta 9-desaturase reaction and, if so, whether vaccenic acid could substitute for CLA as an anticancer agent. In Study 1, rats were fed 1%, 2%, or 3% vaccenic acid in their diet, and tissue levels of CLA and CLA metabolites were determined in liver and mammary gland. In general, concentrations of CLA and CLA metabolites increased proportionately with an increase in vaccenic acid intake, at least up to the 2% dose level. Beyond this dose, there was clearly a plateauing effect. Thus vaccenic acid concentration increased from an undetectable level in the control to 78.5 nmol/mg lipid in the liver of rats fed a 2% vaccenic acid diet. This was accompanied by an increase in CLA from 2.3 to 33.6 nmol/mg lipid. These changes were also mirrored in the mammary gland, where increases in vaccenic acid (from 27.5 to 163.2 nmol/mg lipid) and CLA (from 17.8 to 108.9 nmol/mg lipid) were similarly observed. Vaccenic acid at 2% produced a CLA concentration in the mammary gland that was historically associated with a positive response in tumor inhibition based on our past experience. This provided the basis for selecting 2% vaccenic acid in Study 2, which was designed to evaluate its efficacy in blocking the development of premalignant lesions in the rat mammary gland. In this experiment, formation of histologically identifiable pathology due to intraductal proliferation of terminal end bud cells of mammary epithelium was used as the end point of analysis at 6 wk after carcinogen administration. Treatment with vaccenic acid reduced the total number of these premalignant lesions by approximately 50%. We hypothesize that the anticancer response to vaccenic acid is likely to be mediated by its endogenous conversion to CLA via delta 9-desaturase.

Modulation of lipid metabolism and vitamin A by conjugated linoleic acid

The term conjugated linoleic acid (CLA) refers to a collection of positional and geometrical isomers of octadeca- dienoic acid with conjugated double bonds. CLA has been shown to possess several beneficial activities in different experimental models, however, out of 28 isomers only two, c9, t11 and t10, c12 have been thus far demonstrated to be biologically active. The discovery that it can be elongated and desaturated as a regular fatty acid in human and animal tissues brought a new possibility that its activity may be related to its properties as a peculiar unsaturated fatty acid. In fact, CLA is able to be incorporated in lipid classes as oleic acid, accumulating in those tissues rich in neutral lipids; to be metabolized as linoleic acid and so influencing linoleic acid desaturation and elongation; and to be beta oxidized in peroxisomes which may account for, through activation of PPARs, its ability to increase free retinol levels and influence gene expression. These activities are amplified where CLA accumulates more such as mammary and adipose tissues and may explain its peculiar beneficial properties, at relative low dietary concentrations, in these tissues. Furthermore, it has been demonstrated that CLA can be endogenously formed by delta 9 desaturation of vaccenic acid (t11 18:1) thus forming the isomer c9, t11. Either endogenously formed or through dietary intake, CLA showed to be metabolized in the same way and to exert the same biological properties. We may conclude that a regular intake of CLA, or/and vaccenic acid as its precursor, should work as an excellent preventive agent by modulating lipid metabolism in target tissues thus conferring protection against the attack of insults of different type.

Primary chemotherapy in stage IV ovarian cancer. A prospective phase II study

BACKGROUND AND RATIONALE

Non-curative surgical cytoreduction of advanced tumors is associated with increased proliferation of the remaining tumor cells. Thus, appropriate preoperative chemotherapy should prevent both cell proliferation and the increase of resistant cells. The aim of the present study was to evaluate the efficacy and toxicity of primary chemotherapy (P-CT) in previously untreated patients with stage IV ovarian cancer (OC).

PATIENTS AND METHODS

Thirty-four patients with stage IV OC were treated from January 1993 to April 2000 with P-CT. Eligibility criteria included: histologically or cytologically confirmed, unresectable stage IV OC and performance status < or = 3. P-CT consisted of four courses of carboplatin, cyclophosphamide and epirubicin until October 1996, and paclitaxel, carboplatin thereafter. Surgery followed P-CT. After the operation patients received two further courses of chemotherapy that were tailored according to their individual response. Median (M) age was 61 years, range 32-73; median performance status was 2. A total number of 197 courses of CT were administered, median 5.7 per patient.

RESULTS

Complete or partial response (CR, PR) was observed in 28 patients (response rate 82%, 95% CI: 65.4% to 93.2%), disease stability and progression (SD, PD) was observed in three and three patients, respectively. Median time to progression was 16.45 months (range 4.8-90.4+), median survival time was 28 months (range 4.5 - 90.4+): 1-year survival rate was 94%. Toxicity according to WHO: nausea and vomiting grade (G) 2, 30% of patients; gastrointestinal G 2-3, 20% of patients; alopecia G 3, 88% of patients; hematological G 3-4, 73% of patients; neurologic G 2, 12% of patients. Nine pathological CRs were observed.

CONCLUSION

Neoadjuvant treatment with CBDCA with either CTX and EPI or Taxol is feasible and shows activity in OC.

Esterification of fatty acids using nylon-immobilized lipase in n-hexane: kinetic parameters and chain-length effects

The esterification of long-chain fatty acids in n-hexane catalyzed by nylon-immobilized lipase from Candida rugosa has been investigated. Butyl oleate (22 carbon atoms), oleyl butyrate (22 carbon atoms) and oleyl oleate (36 carbon atoms) were produced at maximum reaction rates of approximately equal to 60 mmol h(-1) g(-1) immobilized enzyme when the substrates were present in equimolar proportions at an initial concentration of 0.6 mol l(-1). The observed kinetic behavior of all the esterification reactions is found to follow a ping-pong bi-bi mechanism with competitive inhibition by both substrates. The effect of the chain-length of the fatty acids and the alcohols could be correlated to some mechanistic models, in accordance with the calculated kinetic parameters.

Effects of bovine serum albumin heterogeneity on frontal analysis with anion-exchange media

The presence of dimers in commercial bovine serum albumin (BSA) samples of nominal high purity is investigated along with their effects on the frontal analysis behavior of preparative anion-exchange media. Size-exclusion and analytical anion-exchange chromatography are used to determine the relative amounts of monomer and dimer for two samples of BSA. While the amount of dimer was generally low, its impact on adsorptive behavior is significant. Equilibrium experiments demonstrate that the anion-exchange media binds the dimer more strongly, leading to an unequal distribution of the monomer and dimer between the two phases. Analysis of the breakthrough behavior of BSA reveals that the monomer breaks through prior to the dimer. This leads to the characteristic tailing breakthrough curve often seen with BSA. Breakthrough experiments carried out using dimer-free BSA confirm that the extreme tailing observed with the commercial samples is curtailed by removing the dimer.

gamma-Hydroxybutyric acid and baclofen decrease extracellular acetylcholine levels in the hippocampus via GABA(B) receptors

The effect of gamma-hydroxybutyric acid (GHB) and baclofen, a GABA(B) receptor agonist, on extracellular hippocampal acetylcholine levels was studied in freely moving rats by microdialysis. GHB (200 and 500 mg/kg, i.p.) reduced in a dose-dependent manner, extracellular hippocampal acetylcholine concentrations and this effect was prevented by the GABA(B) receptor antagonist (2S)(+)-5,5-Dimethyl-2-morpholineacetic acid (SCH 50911), at the dose of 20 mg/kg (i.p.), while the putative GHB receptor antagonist 6,7,8,9-Tetrahydro-5-hydroxy-5H-benzocyclohept-6-ylideneacetic acid (NCS 382) was ineffective. Similar to GHB, the GABA(B) agonist baclofen (10 and 20 mg/kg, i.p.) produced a dose-related reduction in extracellular acetylcholine concentrations which was prevented by SCH 50911. These findings indicate that GHB-induced reduction of hippocampal acetylcholine release is mediated by GABA(B) receptors and support a possible involvement of hippocampal GABA(B) receptors in the control of cognitive processes and in the claimed amnesic effect of GHB intoxication.

Protein adsorption on novel acrylamido-based polymeric ion-exchangers. III. Salt concentration effects and elution behavior

The effect of salt concentration on the adsorption and desorption of BSA has been determined for a polymeric anion-exchanger based on acrylamido monomers. The material investigated possesses a high adsorption capacity at low salt concentration and the bound protein can be recovered quantitatively at high salt concentrations. The effects of salt on adsorption and desorption rates were evaluated from batch and shallow-bed experiments, and a model was developed to describe the data quantitatively. The adsorption capacity decreases as the salt concentration is increased, but both adsorption and desorption rates increase at higher salt concentrations. The predictability of the behavior of columns packed with this material was examined by comparing model predictions and experimental results obtained in laboratory columns. In general, a good agreement was obtained between predicted and experimental breakthrough and elution profiles, especially in shorter columns. Thus, the model allows a prediction of the effects of column length, mobile phase flow-rate, protein feed concentration, and salt concentration on dynamic capacity, productivity, and on the concentration of product fractions.

Effects of chronic Delta(9)-tetrahydrocannabinol treatment on hippocampal extracellular acetylcholine concentration and alternation performance in the T-maze

Delta(9)-Tetrahydrocannabinol (Delta(9)-THC), the psychoactive ingredient of cannabis sativa, reduces both extracellular hippocampal acetylcholine concentration and correct alternation tasks in the T-maze. The principal aim of this study was to determine whether a chronic Delta(9)-THC treatment would induce tolerance both to the reduction of extracellular hippocampal acetylcholine concentration and memory deficit produced by the drug. Our results show that a chronic Delta(9)-THC treatment (5mg/kg, i.p., twice daily for two weeks) did not produce tolerance to the inhibitory effects induced by the drug. Moreover, no strict temporal correlation between the two Delta(9)-THC effects was observed: the inhibition in extracellular acetylcholine concentration appeared only 80 min after treatment, while the reduction of correct alternation tasks in the T-maze began after 20 min. The cognitive and cholinergic effects induced by a chronic Delta(9)-THC treatment were completely blocked by the CB(1) cannabinoid receptor antagonist SR 141716A, indicating an involvement of CB(1) cannabinoid receptors in the persistent negative effects induced by the drug. These findings confirm the proposition that CB(1) cannabinoid receptors mediate the negative effects induced by Delta(9)-THC both on hippocampal extracellular acetylcholine concentration and correct alternation tasks in the T-maze, and they indicate that these effects may be differentiated. However, the major outcome of this work is the demonstration that no tolerance to the two inhibitory effects develops after a chronic Delta(9)-THC treatment.

Melatonin reduces anxiety induced by lipopolysaccharide in the rat

In male Sprague-Dawley rats intraperitoneal (i.p.) injection of Escherichia coli lipopolysaccharide (0.25, 0.50 and 1 mg/kg) increased anxiety levels. This effect was reversed by a prior, concomitant, and subsequent i.p. treatment with melatonin (4 and 6 mg/kg). As the effects of melatonin upon the actions induced by lipopolysaccharide were reversed by the melatonin receptor antagonist luzindole (30 and 60 mg/kg, i.p.), we argued that they are, but not only, melatonin receptor mediated. These findings, in accordance with our previous works, suggest that melatonin could be useful in the treatment of sickness behaviour associated with systemic infection diseases or as adjuvant in the anti-anxiety therapy.

Distribution of conjugated linoleic acid and metabolites in different lipid fractions in the rat liver

Conjugated linoleic acid (CLA) is known to provide certain health benefits in experimental animal models. The major CLA isomer in food is c 9,t11-CLA. A primary objective of this study was to investigate the uptake of c 9,t11-CLA and its downstream metabolites into various lipid fractions in the liver of rats fed either a high or low CLA diet (containing 0.1 or 0.8 g CLA/100 g diet, respectively). As expected, the levels of all conjugated diene (CD) fatty acids (CD 18:2 + CD 18:3 + CD 20:3 + CD 20:4) were elevated about 8-fold in the high CLA diet group. However, there was no change in the distribution of CLA and CLA metabolites into various lipid fractions due to CLA intake. Unlike linoleic acid or gamma-linolenic acid, which were distributed mainly in phospholipids, CD 18:2, CD 18:3, and CD 20:3 were incorporated primarily in neutral lipid. Furthermore, the incorporation of all nonconjugated unsaturated fatty acids was not perturbed by CLA. Regardless of the level of CLA in the diet, CD 20:4 was predominantly enriched in phosphatidylserine and phosphatidylinositol. In contrast, arachidonic acid was primarily enriched in phosphatidylcholine and less so in phosphatidylethanolamine. The above findings may have potential implication regarding the role of CLA in modulating eicosanoid metabolism.

Surgical treatment of invasive carcinoma of the vulva. Our experience

OBJECTIVE

The purpose of this study was to investigate the clinical findings, treatment and outcome of patients with vulvar carcinoma in the L'Aquila area.

METHODS

Fifteen cases of vulvar carcinoma seen between September 1991 and December 1999 at the Department of Obstetrics and Gynecology of the University of L'Aquila were reviewed. Clinical, pathologic, surgical and follow-up data were collected from patient records. Mean age at diagnosis was 66.4 years. All patients were evaluated through a careful medical history and physical examination, vulvoscopy, abdomino-pelvic CT or MR, urethrocystoscopy, rectocolonscopy and SCC, and CEA determination. Radical surgery included six patients treated by the Taussig-Way operation. Modified radical surgery accounted for nine patients treated by the Byron three-incision approach.

RESULTS

The major early complication was groin wound breakdown which occurred in four cases. The major late complication was chronic leg edema which was reported in six patients. The average number of nodes removed per patient was 19.5. Seven patients (46.7%) had a T2N0M0 pathologic stage, four (26.7%) were T2N1M0, four (26.7%) T1N0M0. Five patients died of local and distant recurrences within 37 months after surgical treatment; ten patients are alive, nine are apparently free from disease whereas one presented local and systemic recurrence within 18 months after surgery.

CONCLUSIONS

Vulvar carcinoma predominantly affects older women. Most patients in our series (11/15) had tumors more than 2 cm in diameter. Although the vulva is an external organ and early detection should be achieved, many patients presented with extensive primary lesions due to both patient and physician delay. Stage of disease, tumor size, and nodal metastases are potential prognostic factors useful in selecting patients for a more conservative surgical approach.

5'-Methylthioadenosine administration prevents lipid peroxidation and fibrogenesis induced in rat liver by carbon-tetrachloride intoxication

BACKGROUND

5'-Methylthioadenosine (MTA), a product of S-adenosylmethionine (SAM) catabolism, could undergo oxidation by mono-oxygenases and auto-oxidation. MTA and SAM effects on oxidative liver injury were evaluated in CCl4-treated rats.

METHODS

Male Wistar rats were killed 1-48 h after poisoning with a single intraperitoneal CCl4 dose (0.15 ml/100 g) or with the same dose twice a week for 14 weeks. Daily doses of MTA or SAM (384 micromol/kg), started 1 week before acute CCl4 administration or with chronic treatment, were continued up to the time of sacrifice.

RESULTS

Acute and chronic CCl4 intoxication decreased MTA and, to a lesser extent, SAM and reduced glutathione (GSH) liver levels. MTA administration increased liver MTA without affecting SAM and GSH. SAM treatment caused complete/partial recovery of these compounds. MTA and, to a lesser extent, SAM prevented an increase in liver phospholipid hydroperoxides in acutely and chronically intoxicated rats and in prolyl hydroxylase activity and trichrome-positive areas in chronically treated rats. MTA prevented upregulation of Tgf-beta1, Collagen-alpha1 (I) and Tgf-alpha genes in liver of chronically intoxicated rats, and TGF-beta1-induced transdifferentiation to myofibroblasts and growth stimulation by platelet-derived growth factor-b of stellate cells in vitro.

CONCLUSIONS

MTA and SAM protect against oxidative liver injury through partially different mechanisms.

Asymmetric ketone reduction with immobilized yeast in hexane: biocatalyst deactivation and regeneration

There is a need to develop methods for producing enantiomerically pure pharmaceuticals because the racemic mixtures made today will probably not be allowed in the future. Synthetic chiral catalysts are being developed for this purpose, as well as new product separation techniques. Another possible option is to use biocatalysts, such as purified enzymes or whole microbial cells, since these can result in the production of mostly a single enantiomer. This study emphasizes the use of alginate-entrapped yeast cells to catalyze the reduction of ketones as a model system. The emphasis is on the factors that might limit the reactivity of such cells, such as equilibrium conditions, substrate or product inhibition, solvent toxicity, loss of cell viability, or the degradation of intracellular levels of enzymes or cofactors. It was found that there was a progressive loss of catalytic activity of the immobilized yeast cells, which appeared to be mainly associated with a loss of cell viability and a decline of intracellular NAD(H) levels during the reaction. The other factors investigated did not have a large effect. A regeneration scheme was developed in order to replenish the intracellular NAD(H) lost during the reaction, which involved removing the biocatalyst from the reaction and supplying the cells with a nutrient source. This resulted in an increase in the NAD(H) to initial levels and also resulted in a maintenance of the ketone reduction rate over time.

Protein adsorption on novel acrylamido-based polymeric ion-exchangers. I. Morphology and equilibrium adsorption

The protein uptake equilibrium and particle morphology are determined for novel polymeric ion-exchange media based on acrylamido monomers with a high density of functional groups and a variety of morphological characteristics. The study considers two anion-exchangers and a cation-exchanger. Physical properties determined experimentally include particle density, ion-exchange capacity, particle size distribution, and equilibrium isotherms for model proteins. The pore structure was evaluated using size exclusion chromatography with neutral probe molecules and transmission electron microscopy. For the anion-exchangers, two types of structures were inferred. The first is comprised of particles that contain a low-density gel supported by denser polymer aggregates. This material had a very low size-exclusion limit for neutral probes, but exhibited an extremely high and reversible protein adsorption capacity (280-290 mg BSA/ml). The second structure is comprised of particles with large, open macropores. While the size-exclusion limit was very high, the protein adsorption capacity was low (60 mg BSA/ml). Moreover, the adsorption was nearly irreversible. The physical structure of the cation-exchanger appeared to be intermediate between those of the anion-exchangers, containing both large pores and smaller pores yielding an intermediate, but reversible, protein uptake capacity (120-130 mg alphaCHY/ml). The different behavior of these materials with regards to protein adsorption correlates well with their physical structure. For these ion-exchangers, high protein adsorption capacities are attained when a low-density polymer gel with a high concentration of functional groups is present.