Determination of Water (Moisture) and Dry Matter in Animal Feed, Grain, and Forage (Plant Tissue) by Karl Fischer Titration: Collaborative Study

A Karl Fischer method for determining water (dry matter) in animal feed and forages was collaboratively studied. Water was extracted from animal feed or forage material into methanol–formamide (1 + 1) directly in the Karl Fischer titration vessel by high-speed homogenization. The water was titrated at 50°C with one-component Karl Fischer reagent based on imidazole. Ten blind samples were sent to 9 collaborators in the United States, Canada, and Germany. The within-laboratory relative standard deviation (repeatability) ranged from 1.14 to 6.99% for water or from 0.09 to 0.56% for dry matter. Among-laboratory (including within-) relative standard deviation (reproducibility) ranged from 5.35 to 10.73%, or from 0.44 to 0.77% for dry matter. The authors recommend that the method be adopted as Official First Action by AOAC INTERNATIONAL. A comparable alternative extraction procedure using boiling methanol is also recommended for Official First Action.

Clinical visible signs of disease activity in vitiligo: a systematic review and meta-analysis

Vitiligo is an unpredictable depigmenting disorder for which a static method to assess disease activity is lacking. Presence of certain skin manifestations may be indicative of disease activity. Here, we evaluated the current evidence for an association between clinical signs and reported disease activity in vitiligo. A systematic review and meta-analysis was performed based on a search in PubMed, Embase and Cochrane Library. Literature reporting skin manifestations and disease activity was analysed based on descriptive analyses and, if applicable, odd ratios. Forty-six observational studies were selected and analysed, including 28 case reports. Reported clinical signs in relation to active vitiligo were as follows: Koebner's phenomenon, confetti-like depigmentations, tri- and hypochromic lesions (including poorly defined borders), inflammatory borders/areas, itch and leukotrichia. Based on this search, strong evidence was found for Koebner's phenomenon. Poorly defined borders and confetti lesions are potential markers, although more data are needed to confirm this. Evidence for other skin manifestations was inconclusive, whereas case reports on inflammatory borders were indicative of active disease. Limitations included the lack of randomized controlled trials, large-scale prospective studies and heterogeneity due to inconsistent definitions. This systematic review urges the vitiligo community to come forward with consensus-based definitions as well as a reliable scoring system to assess these clinical signs and to design optimal trials to investigate their true predictive value.

Adult vaccination for pneumococcal disease: a comparison of the national guidelines in Europe

Pneumococcal disease constitutes a major global health problem. Adults aged over 50 years and younger adults with specific chronic health conditions are at risk for invasive pneumococcal disease, associated with substantial morbidity and mortality. In Europe, two vaccine types are used in adults for pneumococcal immunization: pneumococcal polysaccharide vaccine (PPV23) and pneumococcal conjugate vaccine (PCV13). To provide an overview and to compare the national guidelines for pneumococcal immunization for adults in Europe. In November 2016, national guidelines on pneumococcal vaccination for adults of 31 European countries were obtained by Google search, the website of European Centre for Disease Prevention and Control, and contacting public health officials. In our analysis, we distinguished between age-based and risk-based guidelines. In October 2017, we used the same method to retrieve guideline updates. We observed great variability regarding age, risk groups, vaccine type, and use of boosters. In age-based guidelines, vaccination is mostly recommended in adults aged over 65 years using PPV23. Boosters are generally not recommended. An upper age limit for vaccination is reported in three countries. In the immunocompromised population, vaccination with both vaccines and administration of a booster is mostly recommended. In the population with chronic health conditions, there is more heterogeneity according vaccine type, sequence, and administration of boosters. Asplenia is the only comorbidity for which all countries recommend vaccination. The great variability in European pneumococcal vaccination guidelines warrants European unification of the guidelines for better control of pneumococcal disease.

Ganglioradiculitis (Sensory Neuronopathy) in a Dog: Clinical, Morphologic, and Immunohistochemical Findings

A 9-year-old Labrador Retriever was diagnosed with ganglioradiculitis (sensory neuronopathy). This idiopathic disease of mature dogs is characterized by a profound loss of sensory nerve function due to mononuclear inflammatory infiltration of peripheral ganglia and spinal nerve roots, with destruction of sensory neurons. Immunohistochemistry demonstrates that the infiltrating cells are primarily T lymphocytes and that immunoglobulins are not present on the cell membranes of affected neurons. The pathogenesis of ganglioradiculitis remains unclear, but the evidence points to a cell-mediated immune mechanism.

[Pulmonary hypertension due to left heart disease: recommendations of the Cologne Consensus Conference 2010]

The 2009 European Guidelines on Diagnosis and Treatment of Pulmonary Hypertension have been adopted for Germany. While the guidelines contain detailed recommendations regarding pulmonary arterial hypertension (PAH), they contain only a relatively short paragraph on other, much more frequent forms of PH such as PH due to left heart disease. Despite the lack of data, targeted PAH treatments are increasingly being used for PH associated with left heart disease. This development is of concern. On the other hand, PH is a frequent problem that is highly relevant for morbidity and mortality in patients with left heart disease, so that it may be speculated whether selected patients may benefit from targeted PH therapy. It that sense, the practical implementation of the European Guidelines in Germany requires the consideration of several specific issues and already existing novel data. This requires a detailed commentary to the guidelines, and in some aspects an update already appears necessary. In June 2010, a Consensus Conference organized by the PH working groups of the German Society of Cardiology (DGK), the German Society of Respiratory Medicine (DGP) and the German Society of Pediatric Cardiology (DGPK) was held in Cologne, Germany. This conference aimed to solve practical and controversial issues surrounding the implementation of the European Guidelines in Germany. To this end, a number of working groups was initiated, one of which was specifically dedicated to PH due to left heart disease. This commentary summarizes the results and recommendations of this working group.

Expression analysis of imbalanced genes in prostate carcinoma using tissue microarrays

To identify candidate genes relevant for prostate tumour prognosis and progression, we performed an exhaustive gene search in seven previously described genomic-profiling studies of 161 prostate tumours, and four expression profiling studies of 61 tumours. From the resulting list of candidate genes, six were selected for protein-expression analysis based on the availability of antibodies applicable to paraffinised tissue: fatty acid synthase (FASN), MYC, β-adrenergic receptor kinase 1 (BARK1, GRK2) the catalytic subunits of protein phosphatases PP1α (PPP1CA) and PP2A (PPP2CB) and metastasis suppressor NM23-H1. These candidates were analysed by immunohistochemistry (IHC) on a tissue microarray containing 651 cores of primary prostate cancer samples and benign prostatic hyperplasias (BPH) from 175 patients. In univariate analysis, expression of PP1α (P=0.001) was found to strongly correlate with Gleason score. MYC immunostaining negatively correlated with both pT-stage and Gleason score (P<0.001 each) in univariate as well as in multivariate analysis. Furthermore, a subgroup of patients with high Gleason scores was characterised by a complete loss of BARK1 protein (P=0.023). In conclusion, our study revealed novel molecular markers of potential diagnostic and therapeutic relevance for prostate carcinoma.

A Bloembergen?Purcell?Pound 13 C NMR relaxation study of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate

The molecular structure and rotational motion of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) were studied over a wide temperature range using the Bloembergen-Purcell-Pound 13C NMR spin-lattice relaxation method and NOE factors. Examination of the spin-lattice relaxation times (T1) and the rates (R1 = 1/T1) of the 1-butyl-3-methylimidazolium cation reveals the relative motions of each carbon in the imidazolium cation. The rotational characteristics of the [BMIM] cation are supported by ab-initio molecular structures of [BMIM][PF6] using density functional theory (DFT) and Hartree-Fock (HF) methods. The ab-initio gas phase structures of [BMIM][PF6] indicate that the 1-butyl-3-methylimidazolium C2 hydrogen, the ring methyl group, and the butyl side-chain hydrogen atoms form hydrogen bonds with the hexafluorophosphate anion.

Molecular structure, reorientational dynamics, and intermolecular interactions in the neat ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate

Results on the molecular and liquid structure and the reorientational dynamics are reported for the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]). In quantum-chemical calculations for [BMIM][PF6] in the gas phase, hydrogen bonding between the proton at carbon 2 in the aromatic ring and the fluorine atoms of the hexafluorophosphate anion was found. From the analysis of 13C relaxation data, the reorientational motions were evaluated, and the Vogel-Fulcher-Tammann and Arrhenius activation energies for the overall and internal reorientational motions, respectively, of the different 13C-1H vectors are given as well as correlation times at 300 K. By performing molecular dynamics (MD) simulations, pair distribution functions between moieties in the cation and the phosphorous atom in the anion were determined. The pair distribution function for the proton at carbon 2 exhibits a particular sharp and strong maximum indicating a strong interaction with the anion. The quantum-chemical calculations, the motional parameters, and the results from the MD simulations support the existence of hydrogen bonding and the formation of ion pairs in the ionic liquid.

Randomized clinical trial of cryotherapy versus laser photocoagulation for retinopexy in conventional retinal detachment surgery

PURPOSE

To investigate whether the method of retinopexy influences the visual recovery rate and the breakdown of the blood-ocular barrier after conventional retinal detachment surgery.

METHODS

Forty-eight patients (48 eyes) with primary rhegmatogenous retinal detachment entered into the study. All eyes were phakic, had an attached macula, and were scheduled for conventional scleral buckling surgery. Patients were randomly assigned to have either laser or cryotherapy for retinopexy. All visual acuity and flare measurements were performed by a masked observer. The interventional procedure was cryopexy at the time of scleral buckling surgery or postoperative (4 weeks) laser photocoagulation. Visual acuity testing with ETDRS chart and aqueous flare measurement with laser flare photometry were performed by a masked observer at standard intervals: preoperatively and 1 day, 7 days, 4 weeks, and 10 weeks postoperatively. Analysis of covariance by multiple linear regression was used for statistical evaluation.

RESULTS

Postoperative flare values from patients receiving cryotherapy were significantly higher at each measurement point in time (P < or =.001). The visual recovery was slower in the patients receiving cryotherapy (1 week, P =.003; 4 weeks, P =.03; 10 weeks, P =.081).

CONCLUSION

Laser flare photometry proved sufficiently sensitive to quantify an increase in aqueous flare after limited external retinal cryotherapy. Postoperative flare, as a measure of blood-ocular barrier breakdown, was significantly higher and visual recovery slower in the cryotherapy group. Visual acuity after 10 weeks was not significantly different between both groups.

B-cell neoplasia associated gene with multiple splicing (BCMS): the candidate B-CLL gene on 13q14 comprises more than 560 kb covering all critical regions

Deletions in chromosomal band 13q14.3 occur in >50% of B-cell chronic lymphocytic leukemias (B-CLL) and mantle cell lymphoma, indicating the localization of a tumor suppressor gene involved in the pathomechanism of these diseases. Within a 400 kb recurrently deleted segment at least two minimally deleted subregions had been reported. For the two genes residing in the proximal subregion, initially named LEU1 and LEU2, a pathogenic role has not yet been established. We report here that LEU1 is only a small portion of a large gene, which spans all previously reported critical subregions including the distal subregion. This gene, designated B-cell neoplasia-associated gene with multiple splicing (BCMS), is composed of at least 50 exons spanning >or=560 kb of genomic DNA and is expressed in more than 20 RNA splicing variants. While tissue-specific expression of RNA variants was observed, there was no evidence for the expression of a variant specific for B-CLL. Sequence analysis of the RNA variants suggests that BCMS transcripts belong to the group of non-coding RNAs. The alignment of the gene with all critical subregions provides a strong argument for BCMS being the most likely candidate for the tumor suppressor gene in 13q14 involved in the leukemogenesis of B-CLL. Due to the limited understanding of functional RNAs, however, it remains difficult to prove the pathogenic role of BCMS.

BCMSUN, a candidate gene for B-cell chronic lymphocytic leukemia and mantle-cell lymphoma, has an independently expressed homolog on 1p22-p31, BCMSUN-like

The most frequent chromosomal imbalance in B-cell chronic lymphocytic leukemia (B-CLL) and mantle-cell lymphoma (MCL) is loss of material from 13q14.3. BCMSUN (previously Leu2, t4, cDNA 1B4) is one of 3 proposed candidate genes isolated from the minimally deleted region. We identified a homolog of BCMSUN, termed BCMSUNL (for BCMSUN-like). Radiation-hybrid mapping with a PCR-amplified fragment and fluorescence in situ hybridization with 2 PAC clones containing coding information for BCMSUNL revealed its localization at 1p22-p31. Interphase fluorescence in situ hybridization, however, revealed that the BCMSUNL gene locus is not part of the critical deletion region of 1p22 in MCLs. Analysis of DNA sequences derived from the respective PAC clones and available in public databases uncovered an intronless structure of BCMSUNL. Compared to BCMSUN, the new gene lacks exon 2 and shows 90.3% homology on the nucleic acid level. Both genes are expressed in peripheral blood lymphocytes from healthy donors as well as B-CLL and MCL tumors, with retention of genetic material at 13q14.3. Therefore, analysis of the candidate tumor-suppressor gene BCMSUN at 13q14.3 must be based on assays that distinguish between the 2 homologous genes.

BCL10 is not the gene inactivated by mutation in the 1p22 deletion region in mantle cell lymphoma

The BCL10 gene has recently been cloned from the 1p22 breakpoint of the translocation t(1 ;14)(p22;q32) observed in mucosa-associated lymphoid tissue (MALT) lymphoma. BCL10 was shown to be a proapoptotic-signaling gene encoding a protein that contains an amino-terminal caspase recruitment domain (CARD). Mutations within the BCL10 coding region resulting in truncated BCL10 proteins with loss of their proapoptotic function and preservation of their NF-kappaB activating function were detected in MALT lymphoma. Based on these findings it was proposed that BCL10 might have tumor suppressor function. Deletions involving 1p22 are commonly observed in mantle cell lymphoma (MCL). To investigate its role in MCL we have analyzed a series of 15 MCL for deletion and mutation of BCL10. Monoallelic 1p22 deletions were detected by fluorescence in situ hybridization in five of the 15 cases and were shown to affect BCL10 in all cases. BCL10 was screened for mutations by DNA sequencing of RT-PCR amplified transcripts. In none of the 15 MCL cases studied were mutations found in the BCL10 coding region. A previously reported polymorphism exhibiting a silent 24C > G substitution was found in eight MCL cases and in four healthy probands. A missense mutation 13G >T resulting in a substitution of a serine by an alanine was seen in one of the controls. Our results strongly suggest that BCL10 is not the candidate tumor suppressor gene inactivated by deletion or mutation in band 1p22 in MCL.

Reduction mammaplasty in postburn breasts

Thermal injury to the anterior chest in the adolescent girl can lead to severe disfigurement of the breasts. Just as in certain non-burn female patients, mammary hyperplasia can occur in patients with previous full-thickness burns of their breasts. Most plastic surgeons have been reluctant to perform reduction mammaplasty in these patients for fear of devascularizing the skin graft or the nipple-areola complex. A series of six patients with full-thickness burns of the breasts and subsequent skin graft coverage before reduction mammaplasty is reported. Four patients had bilaterally burned breasts requiring reduction. Two patients had one burned breast reduced, and one required a balancing procedure on the unburned side. Reduction mammaplasty was performed using the inferior-pedicle technique. The mean amount of tissue removed for the left and right breasts was 454 and 395 g, respectively. There was no nipple loss, hematoma, infection, or major loss of skin flaps. Reduction mammaplasty in this group of patients is safe and carries minimal risk if certain key concepts are followed carefully.

Scalp autografts and hair transfer to the face in the burned child

Hair transfer from split-thickness skin grafts harvested from the scalp is not a widely reported problem. The authors present their experience with hair transfer from scalp autografts in a pediatric burn population, with particular emphasis on hair transfer to the face. They retrospectively reviewed 3307 acute and reconstructive pediatric burn admissions over a 4-year period at a single institution and identified 109 cases in which the scalp had been used as a donor site and in which the patient survived the acute burn period. Data from 73 male and 36 female patients were analyzed with respect to age, race, sex, percent total body surface area burned, graft thickness, number of scalp harvests and time between harvests, and presence of donor site alopecia. Eighteen of the 109 patients had noticeable hair growth from their scalp grafts (17 percent). Fourteen of 18 cases of hair growth involved face or neck grafts (13 percent); the remaining 4 patients had hair growth elsewhere on the body. There was no difference between the two groups (hair growth versus no hair growth) when compared by age, sex, or graft thickness. There was a correlation between larger burn size and greater incidence of hair growth. Those who had multiple harvests of the same scalp donor site were more than twice as likely to have hair transfer (9 of 34 versus 9 of 75 patients), although time between harvests was not a significant variable. Caucasian children represented 77 percent of the study population yet 100 percent of the cases of problem hair growth. Thirty-three percent of the hair growth group (6 of 18 patients) and 4 percent of the remaining patients (4 of 91) had some degree of donor site alopecia. The scalp is a reliable and valuable donor site for skin grafting in children, particularly for facial burns. The authors note a moderate incidence of hair transfer (17 percent) and propose both suggestions for prevention and recommendations for management.

Coronary NIR stent implantation for refractory variant angina

A 44-year-old woman with severe variant angina refractory to maximal medical therapy and at risk of sudden death was successfully treated by a NIR stent implantation on a moderate lesion of LAD. Six months later she was asymptomatic, without in-stent restenosis. This procedure represents an alternative treatment for patients with refractory vasospastic angina.

Tissue expander complications in the pediatric burn patient

Tissue expanders have become a useful adjuvant in pediatric burn reconstruction. We reviewed our experience with tissue expanders from June of 1984 to July of 1995. There were 403 expanders used in 301 patients. Complications relative to specific anatomic areas from July of 1987 to July of 1995 were compared with previously published data in the journal from June of 1984 to June of 1987. Complications were defined as absolute if they resulted in the loss of expanders or in additional surgery, or none of the preoperative plan was satisfied. The relative complications were defined as spotty alopecia, alopecia greater than 50 percent, or the operative plan was only partially satisfied, sometimes implying poor surgical judgment. The overall complication rate for the period June of 1984 to June of 1987 was 30 percent (37 complications in 122 expanders). In the July of 1987 to July of 1995 study, the complication rate was only 18 percent (51 complications in 281 expanders). This was a statistically significant decrease between the periods (p = 0.010). In the recent 8-year period, there was a decrease compared with the previous study in both the absolute and relative complications. The most common absolute complication in this period was infection (15 of 31, 48 percent) with 12 (39 percent) being early infection. With regard to the nine complications in the neck, face, ear, and supraclavicular area, two-thirds were related to leakage or exposure of the expanders, resulting from the tight anatomic area causing mechanical damage of the expanders as well as ischemia to the overlying skin. Early in the study, the lower extremities proved to involve difficult or unsatisfactory areas to expand, and lower extremity expansion was abandoned throughout the remainder of the study period. The overall decrease in absolute and relative complications is likely the result of increased operative experience as well as a developed protocol for the prevention of perioperative complications relating to infection and expansion in high-risk anatomic sites.

The cdc25B phosphatase is essential for the G2/M phase transition in human cells

Cdc25 phosphatases play key roles in cell cycle progression by activating cyclin-dependent kinases. In human cells, cdc25 proteins are encoded by a multigene family, consisting of cdc25A, cdc25B and cdc25C. While cdc25A plays a crucial role at the G1/S phase transition, cdc25C is involved in the dephosphorylation and activation of the mitotic kinase, cdc2/cyclinB. In addition, cdc25C itself is regulated by cdc2/cyclinB which then creates a positive feedback loop that controls entry into mitosis. In this study we show that the activity of cdc25B appears during late S phase and peaks during G2 phase. Both in vitro and in vivo cdc25B is activated through phosphorylation during S-phase. Using a cell duplication, microinjection assay we show that ablation of cdc25B function by specific antibodies blocks cell cycle progression in Hs68 cells by inhibition of entry into mitosis. Cdc25B function neither plays a role in later stages of mitosis nor for the inititation of DNA replication. These results indicate that cdc25B is a mitotic regulator that might act as a ‘starter phosphatase’ to initiate the positive feedback loop at the entry into M phase.

Assessment of the optimal atrioventricular delay in dual chamber-paced patients by a portable scintillation probe (VEST)

BACKGROUND

The optimal atrioventricular delay in dual-chamber pacing differs from patient to patient. The availability of a portable scintillation probe (VEST) enables noninvasive monitoring of left ventricular function.

METHODS AND RESULTS

Hemodynamic variations were measured in 10 patients with programmable DDD pacemakers. The ejection fraction, stroke volume, and diastolic and systolic volume were evaluated, programming six different atrioventricular delays ranging from 75 to 200 msec, to determine the most favorable atrioventricular delay. Comparing left ventricular ejection fraction (LVEF), stroke volume, and end-diastolic and end-systolic volume at each DVI mode with a preceding DVI setting of 75 msec, all parameters at 200 msec were statistically different from those at 100 msec. An increase of LVEF and stroke volume and a decrease of end-systolic volume was found. In only five patients a switch of VVI mode to the optimal DVI mode results in an increase of LVEF of more than 5%.

CONCLUSIONS

Our study stresses the importance of optimizing atrioventricular delay. The VEST system permits these measurements, increasing the accuracy of the determination of optimal atrioventricular delay, and appears to be valuable in the management of patients with cardiac dual-chamber pacemakers.

Kinetics of the transplanted heart. Implications for the choice of field-test exercise protocol

PURPOSE

The transplanted heart shows a slow increase (on transient) of both heart rate (HR) and oxygen consumption (VO2) at the beginning of exercise. The hypothesis used in this study was that this would lead to unacceptably large systematic errors when field predictions of maximal oxygen intake (VO2max) were derived from cycle ergometer tests with a steep ramp function.

METHODS

The subjects (27 patients who had received orthotopic heart transplants 6 months previously, and 45 age-matched control subjects) each performed a rapid progressive cycle ergometer test (increments of 16.7 Watts [W] per minute to subjective exhaustion) and a "steady-state" test (two 6-minute stages at one third and two thirds of peak power output). Time constants for HR and VO2 were determined by fitting single exponent equations to the "steady-state" data and noting the time for the difference from the plateau value to reach 36.8% of its initial value. Heart rate and VO2 also were compared between rapid progressive and "steady-state" tests at one third and two thirds of peak power output.

RESULTS

At one third of peak power output (46 W in patients, 73 W in control subjects), the respective time constants (mean +/- SE [standard error]) were 60.4 +/- 6.4 and 40.5 +/- 3.0 seconds for VO2 (P < .01), and 130.0 +/- 14.3 and 67.9 +/- 10.0 seconds for HR (P < .001). At two thirds of peak power, the corresponding values were 49.2 +/- 5.5 and 34.7 +/- 2.7 seconds for VO2 (P < .05), and 147.9 +/- 13.0 and 122.2 +/- 4.8 seconds for HR (P < .10). Comparing rapid progressive and "steady-state" readings, the control subjects showed identical values for HR and VO2 at one third of peak power, but at two thirds, the rapid progressive test HR lagged behind the "steady-state" value by 8 +/- 3 beats per minute. The cardiac transplant patients showed a larger HR lag in the rapid progressive tests (109 +/- 12 vs 117 +/- 10 beats per minute, P < .05; 125 +/- 14 vs 141 +/- 14 beats per minute, P < .005). Oxygen consumption also tended to lag slightly at two thirds of peak power (118 +/- 76 mL/min, not significant).

CONCLUSIONS

The rapid progressive test protocol yields acceptable field estimates of aerobic power in normal individuals, but the slow acceleration of HR after cardiac transplantation leads to unacceptably large errors if the HR from a rapid progressive test protocol is used to predict maximal oxygen intake (VO2max) in such patients.

Primary structure and function of a second essential member of the heterooligomeric TCP1 chaperonin complex of yeast, TCP1 beta

A role for heterooligomeric TCP1 complex as a chaperonin in the eukaryotic cytosol has recently been suggested both by structural similarities with other chaperonins and by in vitro experiments showing it to mediate ATP-dependent folding of actin, tubulin, and luciferase. Here we present the primary structure of a second subunit of the complex and present genetic and functional analyses. The TCP1 beta amino acid sequence, predicted from the cloned gene, bears 35% identity to TCP1, termed here TCP1 alpha, containing the same highly conserved residues found in the collective sequence of chaperonins. The predicted product was identified as the fastest-migrating species of the TCP1 complex purified from soluble extracts of yeast. The TCP1 beta gene, like TCP1 alpha, is essential. Strains containing lethal disruptions of either gene could not be rescued by additional copies of the other. Spores bearing disruption of either gene germinated as single, large-budded cells. Similarly, large-budded cells were observed following shift to 37 degrees C of strains carrying temperature-sensitive mutations in either TCP1 alpha or TCP1 beta. The arrested cells contained replicated DNA present in single nuclear masses, associated with abnormal tubulin staining patterns, supporting the assertion that mitotic spindle formation and function are impaired. We conclude that TCP1 beta supplies an essential function that partially overlaps with that of TCP1 alpha in acting as a molecular chaperone in tubulin and spindle biogenesis.

Isolation of peroxisome-deficient mutants of Saccharomyces cerevisiae

Two mutants of Saccharomyces cerevisiae affected in peroxisomal assembly (pas mutants) have been isolated and characterized. Each strain contains a single mutation that results in (i) the inability to grow on oleic acid, (ii) accumulation of peroxisomal matrix enzymes in the cytosol, and (iii) absence of detectable peroxisomes at the ultrastructural level. These lesions (pas1-1 and pas2) are shown to be nonallelic and recessive. Crossing of pas1-1 and pas2 strains resulted in diploid cells that had regained the ability to grow on oleic acid as sole carbon source and to form peroxisomes. These pas mutants may provide useful tools for future studies on the molecular mechanisms involved in peroxisomal assembly.

Effect of prolonged glucose infusion on total serum fatty acids and free fatty acids in the rat

This investigation evaluates the effect of prolonged glucose infusion on triglycerides and the composition in total serum fatty acids and free fatty acids in the rat. Glucose infusion over a period of 4 days leads to the following changes: serum triglyceride concentrations are two to three times elevated and serum insulin levels rise 10 times after 12 hours, followed by a steady decrease. Chain elongation is depressed in serum free fatty acids and even more in total serum fatty acids. In serum free fatty acids monodesaturation is unaltered whereas it is highly stimulated in total serum fatty acids. These alterations correlate with the changes of hepatic total fatty acids and do not correlate with changes of fatty acids from epididymal fat pads. The alterations reflect a specific carbohydrate-induced effect on hepatic fatty acid desaturation and chain elongation. They do not support the idea that serum free fatty acids are mainly secreted from the storage pool of adipose tissue; yet, they may have been newly synthesized in fat cells or even in the liver.