INTRAOSSEOUS EPIDERMAL CYST OF THE SACRUM. A Case Report

An unusual case of intraosseous epidermal cyst is reported. The patient, a 45-year-old Japanese female, had suffered from lumbago and dysuria for about 15 years. X-ray examinations and CT scan revealed an expanded osteolytic tumor without marginal sclerotic change within the sacrum, which anteriorly invaded the surrounding soft tissues at the S2/3 level. At this time, chordoma was suspected, but epidermal cyst with foreign body granuloma was finally diagnosed from biopsy and surgical specimens.     

A novel missense mutation in human lactate dehydrogenase B-subunit gene

Reduced activity of serum lactate dehydrogenase (LDH; EC 1.1.1.27) was found in a male medical student during practical examinations of his own blood. Serum LDH isoenzyme pattern showed reductions in activities of the isoenzymes with lower subunit A/B ratios such as LDH1 and LDH2. These findings were indicative of a partial LDH-B subunit deficiency, which was confirmed in erythrocyte hemolysates by Western blotting. Polymerase chain reaction (PCR)-based DNA sequence analysis of the LDH-B subunit gene revealed a heterozygous nucleotide change: a guanine to adenine substitution in codon 69 (GGG --> GAG) at the third exon of the LDH-B subunit gene that resulted in a glycine to glutamic acid substitution (G69E). The mutation was confirmed by PCR-restriction fragment length polymorphism (RFLP) analysis using a mismatched primer to introduce a new NcoI restriction site. The same heterozygous mutation was found in his mother but not in other family members. This mutation involves a residue belonging to alphaC helix in LDH-B subunit protein molecule that functions as an interface for other subunits.     

The molecular weight dependence on the photoconductivity of poly(N-vinylcarbazole)

Poly(N-vinylcarbazole), (PNVC), was prepared, fractionated by gel permeation chromatography, and then characterized by viscometry and vapour pressure osmometry. The fractionated PNVC species with relatively narrow molecular weight distributions were successfully used to measure both their electrical dark-conductivity and photoconductivity using a surface type cell in high vacuum (ca. 10^?7 mm Hg) at room temperature. A molecular weight dependent photoconductivity was found for the fractionated PNVCs with weight average molecular weights in the range of 1,2·10³ to 2,4·10⁵. This observation is in contradiction to Epping's results who has found a molecular weight independent photoconductivity in the molecular weight range of 3·10⁵ to 7·10⁶. Our molecular weight dependence may be well understood in terms of the interrupted overlap of the π-electrons of adjacent carbazolyl groups at the terminal parts of the polymer chains, this effect being all the more stronger the smaller the molecular weight is.     

Sequential changes in plasma lipoprotein(a) as acute phase protein after myocardial infarction and surgery group

The plasma lipoprotein(a), apo AI, apo B, and acute phase proteins, were studied in 21 patients with myocardial infarction and in 11 patients after surgery. In the both groups, C-reactive protein showed a rapid increase, and alpha 1 acid glycoprotein, alpha 1 antitrypsin and lipoprotein(a) followed by a moderate increase and restored to normal values after one month. Lipoprotein(a) increased to a maximum on day 11 in the myocardial infarction group, and on day 8 in the surgery group. Only slight changes in apolipoprotein AI and B were noted. We speculate that lipoprotein(a) is an acute phase protein that plays an important roles in recovery from trauma. Recently it was reported that the amino acid sequence of apolipoprotein(a) is partly identical to that of plasminogen. This sequence suggests that lipoprotein(a) and plasminogen are related immunochemically. We examined by immunoblotting technique whether our antibody for lipoprotein(a) is influenced by a plasminogen in plasma. By enzyme-linked immunosorbent assay, it was found that the purity of plasminogen does not influence determination of lipoprotein(a).     

Assessment of bioequivalence after subcutaneous and intramuscular administration of urinary gonadotrophins

The objective was to demonstrate bioequivalence between s.c. and i.m. administration of Humegon (FSH/LH ratio 1:1) and Normegon (FSH/LH ratio 3:1). In two randomized, single-centre, cross-over studies, 18 healthy volunteers on each formulation were assigned to one of the two administration sequences. Subjects were given single doses of one of the above gonadotrophins after endogenous gonadotrophin production had first been suppressed using high-dose oral contraceptive. Subsequently, rate (Cmax, tmax) and extent (AUC) of absorption of follicle stimulating hormone (FSH) and luteinizing hormone (LH) were determined for 14 days. For Cmax and AUC, analysis of variance (ANOVA) was performed on log-transformed data and for tmax ANOVA was performed on ranks. Intramuscular and s.c. injections of Humegon were bioequivalent with respect to the main pharmacokinetic parameters, being AUC and Cmax of FSH absorption. Intramuscular and s.c. injections of Normegon were bioequivalent with respect to the AUC of FSH and not bioequivalent with respect to the Cmax of FSH. For tmax of FSH as well as for most LH variables of both preparations, bioequivalence could not be proven due to the high intra- and interindividual variability and/or concentrations being close to the detection limit. Thus, the main pharmacokinetic FSH variables after i.m. and s.c. administration of Humegon and Normegon were bioequivalent.      

Serum magnesium concentration is a significant predictor of mortality in maintenance hemodialysis patients

A few studies have reported a correlation between magnesium and co-morbidity and mortality in end-stage renal disease. We investigated the prognostic value of serum magnesium concentration for mortality in 515 patients on maintenance hemodialysis (60 +/- 12 years, 306 males and 209 females; 24% diabetics). The patients underwent follow-up for 51 +/- 17 (mean +/- SD) months, and the relationship between the baseline magnesium concentration (mean of four months) and outcomes was analyzed statistically. During the follow-up period, there were 103 all-cause deaths, including 63 non-cardiovascular deaths. Kaplan-Meier analysis revealed that mortality was significantly higher in the lower magnesium group (< 2.77 mg/dL, i.e. < 1.14 mmol/L, n = 261), compared to that in the higher magnesium group (> or = 2.77 mg/dL, n = 254) (p < 0.001). Multivariate Cox proportional hazard analysis demonstrated that serum magnesium was a significant predictor for mortality (HR [per 1 mg/dL increase], 0.485 [95% CI, 0.241-0.975], p = 0.0424), particularly for non-cardiovascular mortality (HR 0.318 [95% CI, 0.132 to 0.769], p = 0.0110), after adjustment for other confounders, such as age, gender, hemodialysis duration, and the presence of diabetes. In conclusion, it is demonstrated that lower serum magnesium level is a significant predictor for mortality in hemodialysis patients, particularly for non-cardiovascular mortality, although the mechanisms remain to be explored in future studies. Factors affecting serum magnesium concentrations should be investigated in terms of better survival, including dietary magnesium intake. Further extensive studies may be also needed for possible reconsideration of the current dialysate magnesium concentration (1.0 mEq/L, i.e. 0.50 mmol/L used in most countries), one of the strong contributors to the serum magnesium concentrations of dialysis patients.     

Bioresorbable devices made of forged composites of hydroxyapatite (HA) particles and poly-L-lactide (PLLA): Part I. Basic characteristics

Compounds that had neither calcined nor sintered hydroxyapatite (u-HA) particles (particulate size 0.2-20 microns, averaging 3.0 microns, Ca/P = 1.69, and containing CO3(2-) uniformly distributed in a poly-L-lactide (PLLA, Mv: 400 KDa) matrix with a content of 20-50 wt% (with 10% increment) were reinforced into composites by a forging process, which was a unique compression molding, and were then machined on a lathe in order to produce practical radiopaque internal bone fixation devices having high mechanical strength which was maintained during bony union, total resorbability and bioactivity such as bone bonding capability and osteoconductivity. From the results of measurement of various mechanical properties, it was confirmed that the composites generally showed the highest mechanical strength among this type of reinforced bioceramic fibers or particles/bioresorbable polymer composite known to date. The bending strength (Sb) of about 270 MPa was far higher value than that for cortical bone, and the modulus (Eb) of 12 GPa was almost equivalent to that for cortical bone. In particular, the impact strength (Si) was extremely high at about two times the value (166 KJ/m2) of polycarbonate. The in vitro change in Sb, Mv (viscosity average molecular weight), Mw/Mn (molecular weight distribution) and crystallinity, and their relationship with each other was also examined by immersing samples in a phosphate buffer solution (PBS). An immediate decrease in the initial Mv could be found in composites with high u-HA contents (30-50 wt%), although a time-lag stage for degradation where the initial Mv hardly changes was apparent in cases of PLLA-only or in a composite with a low u-HA content (20 wt%). The Sb changed with corresponding decremental curves for the Mv and retained over 200 MPa for up to 24 weeks, the period of time necessary for full bony union, so that the composite satisfied initial mechanical strengths while maintaining them for as long as necessary for internal bone fixation devices. These results supported the idea that there is a difference in the degradation process such that PLLA alone required a period of time to achieve the possibility of hydrolysis into the inner side, whereas composites with high u-HA contents (30-50 wt%) immediately filled with water through to the inner side and were hydrolyzed homogeneously. Many hydroxyapatite crystals deposited and grew on the surface after 3-6 d and generously covered the surface with a fairly thick layer after 7 d of post-immersion in simulated body fluid (SBF) as evaluated by means of energy dispersive X-ray (EDX). This suggested the ability of the radiopaque composites to bond to bone. Since the composites were dense and had ultra-high strength, and the processability was so excellent, many kinds of fine and accurate screws, pins, plates, and other internal bone fixation devices for orthopedic, oral and maxillofacial, craniofacial, and plastic and reconstructive surgeries could be produced by machining treatment. These devices have potential applications for clinical use following the assessment of adaptation during in vivo studies.     

The cognate coat protein is required for cell-to-cell movement of a chimeric brome mosaic virus mediated by the cucumber mosaic virus movement protein

Cucumber mosaic cucumovirus (CMV) and brome mosaic bromovirus (BMV) have many similarities, including the three-dimensional structure of virions, genome organizations, and requirement of the coat protein (CP) for cell-to-cell movement. We have shown that a chimeric BMV with the CMV 3a movement protein (MP) gene instead of its own cannot move from cell to cell in Chenopodium quinoa, a common permissive host for both BMV and CMV. Another chimeric BMV was constructed by replacing both MP and CP genes of BMV with those of CMV (MP/CP-chimera) and tested for its infectivity in C. quinoa, to determine whether the CMV CP has some functions required for the CMV MP-mediated cell-to-cell movement and to exhibit functional difference between CPs of BMV and CMV. Cell-to-cell movement of the MP/CP-chimera occurred, and small local lesions were induced on the inoculated leaves. A frameshift mutation introduced in the CMV CP gene of the MP/CP-chimera resulted in a lack of cell-to-cell movement of the chimeric virus. These results indicate that the viral movement mediated by the CMV MP requires its cognate CP. Deletion of the amino-terminal region in CMV CP, which is not obligatory for CMV movement, also abolished cell-to-cell movement of the MP/CP-chimera. This may suggest some differences in cell-to-cell movement of the MP/CP-chimera and CMV. On the other hand, the sole replacement of BMV CP gene with that of CMV abolished viral cell-to-cell movement, suggesting a possibility that the viral movement mediated by the BMV MP may also require its cognate CP. Functional compatibility between MP and CP in viral cell-to-cell movement is discussed.     

Feasibility of a self‐assembling peptide hydrogel scaffold for meniscal defect: An in vivo study in a rabbit model

The inner avascular zone of the meniscus has limited healing capacity as the area is poorly vascularized. Although peptide hydrogels have been reported to regenerate bone and cartilage, their effect on meniscus regeneration remains unknown. We tested whether the self‐assembling peptide hydrogel scaffold KI24RGDS stays in the meniscal lesion and facilitates meniscal repair and regeneration in an induced rabbit meniscal defect model. Full‐thickness (2.0 mm diameter) cylindrical defects were introduced into the inner avascular zones of the anterior portions of the medial menisci of rabbit knees (n = 40). Right knee defects were left empty (control group) while the left knee defects were transplanted with peptide hydrogel (KI24RGDS group). Macroscopic meniscus scores were significantly higher in the KI24RGDS group than in the control group at 2, 4, and 8 weeks after surgery. Histological examinations including quantitative and qualitative scores indicated that compared with the control group, the reparative tissue in the meniscus was significantly enhanced in the KI24RGDS group at 2, 4, 8, and 12 weeks after surgery. Immunohistochemical staining showed that the reparative tissue induced by KI24RGDS at 12 weeks postimplantation was positive for Type I and II collagen. KI24RGDS is highly biocompatible and biodegradable, with strong stiffness, and a three dimensional structure mimicking native extracellular matrix and RGDS sequences that enhance cell adhesion and proliferation. This in vivo study demonstrated that KI24RGDS remained in the meniscal lesion and facilitated the repair and regeneration in a rabbit meniscal defect model.