Reinforced poly(L-lactic acid) fibres as suture material

In this study, reinforced poly(L-lactic acid) (PLLA) fibers made by a dry-spinning/hot-drawing process were evaluated for use as a suture. The initial tensile strength of the PLLA fibers was lower than the initial tensile strength of the commercially available sutures: PDS, Vicryl, silk, and Ethilon. However, after 12 weeks immersion in a phosphate saline buffer at 37 degrees C, PDS sutures have lower tensile strength than PLLA sutures and the tensile strength of Vicryl was unmeasurable because of fragmentation. Initially, PLLA fibers disintegrated into fibrils during degradation triggering an inflammatory response comparable to degradable multifilament sutures. However, the intensity of the inflammatory response against the PLLA fibers decreased and after 80 weeks implantation in the muscle layer of the abdominal wall of rats it was comparable to the one against Ethilon. The inflammatory response against Ethilon, which is considered to be nondegradable, increased in the same period, probably due to the change in shape. In practice, the handling characteristics of PLLA sutures are superior to the monofilament sutures like PDS and Ethilon and comparable with the multifilament sutures like Vicryl and silk. The knot security of PLLA sutures are expected to be better than the knot security of the monofilament sutures, but this remains to be investigated. It is concluded that dry-spun/hot-drawn (reinforced) PLLA fibers have the potential for use as long-term degradable suture material.

A comparison of polychemotherapy and melphalan/prednisone for primary remission induction, and interferon-alpha for maintenance treatment, in multiple myeloma. A prospective trial of the German Myeloma Treatment Group

406 untreated multiple myeloma patients of stage I (n = 54), II (n = 148) and III (n = 204) were enrolled in the trial. 51/54 stage I and 60/148 stage II patients were asymptomatic and followed without treatment until disease progression (progression free survival: 60% after 4 years for stage I versus 50% after 1 year for stage II). Symptomatic patients of stage I (n = 3/54) and II (n = 88/148) presenting with tumour progression, received melphalan 15 mg/m2 intravenously (i.v.) and prednisone 60 mg/m2 oral days 1-4 (MP). Stage II disease remission rate was 59%, and 50% tumour related survival (TRS) was 59 months. Stage III patients were randomised to receive MP or VBAMDex (vincristine/BCNU/doxorubicin/melphalan/dexamethasone) treatment. 43% of MP treated patients responded compared with 64% of the VBAMDex group. 50% TRS was 36 months in both groups without a detectable difference. 117 responders of stage II and III with stable disease were randomised to receive either IFN-alpha (5 x 10(6) IU, subcutaneous (S.C.) 3 times per week) or no maintenance treatment. The relapse rate in both groups was 50% after 13 months. No survival benefit for IFN alpha treated patients was observed (50% TRS: 45 months).

The suitability of a monofunctional reagent of an undecagold cluster for phasing data collected from the large ribosomal subunits from Bacillus stearothermophilus

An electron density map of the large ribosomal subunit from Bacillus stearothermophilus was obtained at 26 A resolution by single isomorphous replacement (SIR) from a derivative formed by specific quantitative labeling with a dense undecagold cluster. For derivatization, a monofunctional reagent of this cluster was bound to a sulfhydryl group of a purified ribosomal protein, which was in turn reconstituted with core particles of a mutant lacking this protein. The native, mutated, and derivatized 50S ribosomal subunits crystallize under the same conditions in the same space group. Under favorable conditions, crystals of the derivatized subunit proved to be isomorphous with the native ones, whereas the crystals of the mutant may have somewhat different packing. After resolving the SIR phase ambiguity by solvent flattening, the electron density shows a packing that is consistent with the noncrystallographic symmetry found by Patterson searches as well as with the motif observed in electron micrographs of thin sections of the crystals. These studies established that phase information can be obtained from heavy metal clusters, even when the crystals under investigation are unstable and weakly diffracting. These results encouraged further effort at the construction of specifically derivatized crystals from other ribosomal particles that diffract to higher resolution.

[Immunosuppression and infection]

The course of prolonged sepsis is characterized by an initial activation of the immune system followed by the transition into a state of immunosuppression. Accordingly, a series of immunosuppressive substances can be detected in the serum of septic patients. On the cellular level many important functions of the unspecific as well as the specific defense systems of the organism are inhibited. As a consequence, immunosuppression may be contributing to the fact, that patients suffering from prolonged sepsis hardly recover with a high risk to end in multiple organ dysfunction. However, increasing efforts to investigate this problem may result in therapeutic approaches which may help to improve the bad prognosis of sepsis.

Linear arrays of intramembranous particles characterize a subpopulation of epithelial cells in the rabbit caecum

Linear arrays of particles, identical to those in the cup cells of the small intestine, characterize the brush border membrane of a subpopulation of surface epithelial cells in freeze-fracture replicas of the rabbit caecum. Although these cells lack a cup-like indentation of their brush border, we propose that all intestinal epithelial cells showing this arrangement of intramembranous particles in their apical membrane belong to a distinct subpopulation of the epithelial cells. A specific function of this cell type that is related to the linear arrays of particles remains to be determined.

Characterization of human TUR leukemia cells: continued cell cycle progression in the presence of phorbol ester is associated with resistance to apoptosis

Human TUR leukemia cells were generated as a subclone of U937 monoblastoid leukemia cells. There was no obvious difference in the ultrastructure of both cell lines. Like in U937 cells, the expression of monocyte-specific surface markers such as CD14 was negligible in TUR cells. U937 cells and other human myeloid leukemia cell lines (HL-60, THP-1) can be induced by the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) to differentiate along the monocytic pathway. In contrast, exposure to TPA had no effect on the induction of the differentiation program in TUR cells. Thus, the presence of leukocyte integrins including CD11 and CD18, which are significantly induced during TPA-induced differentiation of HL-60, U937 and THP-1 cells, remained nearly unchanged at low levels in both TUR and TPA-treated TUR cells. Furthermore, while expression of major histocompatibility complex (MHC) class II antigens on U937 and TPA-treated U937 cells is barely detectable, there was a significantly constitutive expression of MHC class II, particularly human lymphocyte antigen (HLA-DR) on the surface of TUR and TPA-treated TUR cells. Exposure of human myeloid leukemia cells to TPA is also associated with growth arrest resulting either in a retrodifferentiation process or in programmed cell death. In contrast, TUR cells continued to proliferate in the presence of TPA although the proliferative capacity was continuously reduced by increasing concentrations of TPA.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum levels of end products of nitric oxide synthesis correlate positively with tumor necrosis factor alpha and negatively with body temperature in patients with postoperative abdominal sepsis

Nitric oxide (NO) has been implicated as the principal mediator of the catecholamine resistant vasodilation in septic shock. In this pilot study, we wanted to know if the serum values of nitrite/nitrate (NO2/NO3), the stable endproducts of NO biosynthesis, are elevated in patients with septic shock. Furthermore, we investigated whether there is a correlation between NO2/NO3 serum levels and tumor necrosis factor alpha or interleukin 6. NO2/NO3 serum values were significantly elevated in septic patients compared to controls (72.1 +/- 6.1 vs. 35.7 +/- 9.2 microM, p < .001). There was a significant positive correlation between serum values of NO2/NO3 and tumor necrosis factor alpha (rs = 0.59, p < .001). In contrast, no correlation between NO2/NO3 and interleukin 6 was found. With the exception of body core temperature, which showed a negative correlation with NO2/NO3 levels, no clinical variable turned out to be significantly related to NO biosynthesis. These data indicate a potential role for NO in the clinical course of abdominal sepsis, but points out that more specific data has to be evaluated by prospective clinical studies in order to understand the complex pathophysiologic role of this novel mediator.

Translocation (X;8)(q2?6;q21.3) in a case of systemic mastocytosis

Mastocytosis is a rare disease which occasionally progresses into mast cell leukemia or other myeloid neoplasms. Here we report on a patient with systemic mastocytosis who was found to have a clone with t(X;8)(q2?6;q21.3) and two copies of der(8)t(X;8). In accordance with these results, interphase cytogenetic analysis revealed that 93% of bone marrow cells contained three centromeric regions of chromosome 8. We suggest that the t(X;8) and the duplication of the translocation chromosome 8 may play a role in the progression of the diseases.

Combined immunophenotyping and karyotyping in peripheral T cell lymphomas demonstrating different clonal and nonclonal chromosome aberrations in T helper cells

Combined immunophenotyping and karyotyping was performed in seven cases of peripheral T cell lymphoma with complex aberrant clones. Various lymphocytic cell populations entered mitosis, whereas all aberrant cells belonged to the T helper/inducer cell population. Lymphomas with the same recurrent chromosome aberrations, i.e. inversion inv(14)(q11q32.1) and isochromosome i(8)(q10), had a very similar immunophenotype. The aberrant cells in these cases expressed CD3+, CD4+, CD7+, CD45RO+. The immunophenotypic similarity is underlined in one case of T prolymphocytic leukemia, in whom the aberrant cells lost the CD8 antigen originally present, during cultivation with PHA. In one case of Sézary's syndrome, two or possibly even three different clones as well as nonclonal aberrations were identified within the T (helper/inducer) cell population, providing further evidence that chromosomal instability is a characteristic feature of cutaneous T cell lymphoma.

Folding and stability of the active N-terminal domain of tissue inhibitor of metalloproteinases-1 and -2

The truncated forms of tissue inhibitor of metalloproteinase-1 and -2 (delta TIMP-1 and -2), comprising the N-terminal active domain, are ideal molecules for structural analysis by intrinsic fluorescence as each contains a single conserved tryptophan residue. In this paper we describe studies on their conformational stability, unfolding/refolding kinetics and the environment of the unique tryptophan as judged by its fluorescence properties in the native state and exposure to an external quencher, acrylamide. Two forms of delta TIMP-2 were studied: delta TIMP-2 T21 derived from the full-length cDNA clone isolated from a mixed-tumour library, and delta TIMP-2 A21 containing the highly conserved V18IRAK22 sequence. In all three delta TIMP proteins the tryptophan environments in the native state appeared to be similar, but substantial differences were seen in their conformational stabilities and refolding kinetics. delta TIMP-1 was approximately twice as stable as delta TIMP-2 T21 and 1.4-fold more stable than delta TIMP-2 A21. This stability difference between delta TIMP-1 and delta TIMP-2 was shown to be independent of N-linked glycosylation. delta TIMP-1 and delta TIMP-2 A21 both showed simple two-state refolding kinetics, whereas delta TIMP-2 T21 refolding was more complex and biphasic in character. These differences between delta TIMP-2 T21 and A21 suggest that residue 21 is a structurally important site in the TIMP protein. All three truncated molecules can be considered as stable independent folding domains ideally suited for further structural analysis.

Cytogenetic findings and results of combined immunophenotyping and karyotyping in Hodgkin's disease

Cytogenetic studies were performed in 21 cases of Hodgkin's disease. Fourteen cases revealed chromosomally aberrant clones which could be fully described in 12 cases. Two cases showed different unrelated clones and five cases only single cell aberrations. Recurrent breakpoints were 1p13/21 (six cases), 7q32/34 (five cases), 2p16/21 and 19p13 (four cases each), 4q25/28, 6q15/21 and 12q22/23 (three cases each). In two cases, a translocation between band 19q13 and band 14q11 or 14q32 was found. This finding may indicate that an unknown oncogene in 19p13 is activated by juxtaposition next to a T-cell receptor or immunoglobulin gene in 14q11 or 14q32, respectively. In eight cases each, total or partial monosomy 4 or 6 was present suggesting that tumor suppressor genes in 4q or 6q play a role in tumor development in Hodgkin's disease. Moreover, the aberrant clones lacked the Y-chromosome in men and the second X-chromosome in women in eight out of nine and in two out of three cases, respectively. Although different cell populations, especially T cells, showed mitotic activity in unstimulated short term culture, combined immunophenotyping and karyotyping unequivocally demonstrated that CD30 and CD15 positive Hodgkin and Sternberg-Reed cells represented the chromosomally aberrant clones.

Decreased beta 2-adrenoceptor density and decreased isoproterenol induced c-AMP increase in juvenile type I diabetes mellitus: an additional cause of severe hypoglycaemia in childhood diabetes?

Little is known about the receptor and post receptor mechanisms of sympathoadrenal signal transmission in type I diabetes mellitus. Therefore, we examined the maximum binding of granulocyte beta 2-adrenoceptors and the in vitro c-AMP accumulation in lymphocytes of 24 children and adolescents with diabetes mellitus and 14 similarly aged healthy subjects. The number of high affinity beta 2-adrenoceptors on granulocytes correlated significantly with unstimulated (r = 0.6, P < 0.004) and with isoproterenol stimulated c-AMP values in lymphocytes (r = 0.68, P < 0.0007) showing the proportional changes of beta 2-adrenoceptors and c-AMP in two different cells. The number of beta 2-adrenoceptors on granulocytes was significantly reduced in diabetic as compared to healthy children (median 1397, range 599-3405 vs. 2205, 825-3200 beta 2-adrenoceptors per granulocyte, P = 0.014). Moreover, the percentage in vitro stimulation of c-AMP by isoproterenol in lymphocytes was significantly reduced in diabetic children as compared to healthy individuals (120%, 39%-278% vs. 225%, 66%-500%, P = 0.012). These results indicate a decreased sympathoadrenergic signal transmission in peripheral blood cells as a model for the liver probably contributing to severe hypoglycaemia in diabetic children.

Anterior versus posterior reconstruction after transhiatal oesophagectomy: a randomized controlled trial

In a prospective randomized trial the clinical results after transhiatal oesophagectomy with reconstruction in the anterior mediastinum (51 patients) or posterior mediastinum (45 patients) were compared. There were no differences in age, preoperative risk factors, tumour stage and local (surgical) complications between the two groups. However, reconstruction in the posterior mediastinum was associated with significantly fewer days spent in the intensive therapy unit (9 versus 14), fewer cardiopulmonary complications (13 versus 25 per cent) and lower mortality (30-day mortality rate 2 versus 6 per cent; hospital mortality rate 4 versus 10 per cent). These data show superiority of reconstruction in the posterior mediastinum after transhiatal oesophagectomy. This route is strongly recommended, particularly for patients with cardiopulmonary risk factors.

Structural changes in the apical membrane of lamprey chloride cells after acclimation to seawater

Freeze-fracture replicas demonstrate that the apical membrane of the chloride cells of young adult lampreys (Geotria australis) undergoes a structural change when the animal is acclimated from freshwater to seawater. Although the particles on both the P face and the E face of this membrane are randomly distributed in freshwater animals, they are usually arranged in clusters on both fracture faces in seawater-acclimated animals. Light optical diffraction analysis demonstrates that the particles forming the clusters are periodically arranged. Although comparable clusters of particles have not been recorded in other epithelial membranes that are engaged in transporting ions into a hypertonic environment, they may be involved in the final step of Cl- secretion by the chloride cells of lampreys in seawater.

Endodissection of the thoracic esophagus. Technique and clinical results in transhiatal esophagectomy

OBJECTIVE

Transhiatal esophagectomy (THE), mostly performed in patients with adenocarcinoma of the esophagus, bears the risk of damage to mediastinal structures because the physician's vision is poor during esophageal dissection. The authors report a new endoscopic technique, which enables microsurgical dissection of the esophagus under visual control, that can be performed simultaneously to the abdominal approach. The clinical results in unselected patients with malignant esophageal disease were compared with those of patients undergoing conventional THE.

METHODS

Thirty unselected patients (24 men and 6 women; median age, 60 years; age range, 35 to 80 years), mostly with adenocarcinoma of the esophagus, underwent endodissection between April 1991 and July 1992. Thirty patients, who underwent conventional THE between January 1986 and December 1990, were selected using a matched pair algorithm.

RESULT

Three significant intraoperative complications were recorded during endodissection (one case of mediastinal bleeding; one case of postoperative bleeding; and one case of a lesion of the right main bronchus), and all were managed without further patient morbidity. The mortality rate (30 days) was 6.6% in the endodissection group (vs. 9.9% THE; not significant [NS]). The frequency of postoperative severe pulmonary complications was 13.3% in the endodissection group (vs. 30% in THE; p < 0.05). The rate of recurrent nerve palsy was only 6.6% in the endodissection group (vs. 13.3% in THE; NS).

CONCLUSIONS

Endodissection is especially helpful during esophageal dissection at or above the trachea. It allows identification of mediastinal structures and controlled biopsy of mediastinal lymph nodes. This study showed that endodissection eliminates the "blind angle" during conventional THE, prevents recurrent nerve damage, and reduces pulmonary distress during transhiatal esophagectomy.

Predominant periportal expression of the phosphoenolpyruvate carboxykinase gene in liver of fed and fasted mice, hamsters and rats studied by in situ hybridization

Zonal expression of phosphoenolpyruvate carboxykinase (PCK) mRNA in mouse, hamster and rat liver was studied by in situ hybridization with a radiolabelled rat antisense RNA probe. The abundance of PCK mRNA was determined by Northern blot analysis of total RNA with a digoxigenin-labelled probe. Livers were taken from animals that were sacrificed during the normal day/night cycle and after 29 h fasting. In situ hybridization revealed a heterogeneous distribution pattern of PCK mRNA in the liver of all three species throughout the whole day/night cycle. At the end of the dark period, i.e. at the end of feeding, with rats and mice but at a point of continuous feeding with hamsters, low amounts of PCK mRNA were restricted mainly to the periportal area. At the end of the light period, i.e. at the end of fasting with rats and mice but at a point of continuous feeding with hamsters, PCK mRNA levels were increased to a maximum and extended from the periportal to the intermediate zone. In mouse liver prolonged fasting caused a significant increase in PCK mRNA abundance with a nearly homogeneous distribution within the parenchyma. In hamster and rat liver, however, PCK mRNA levels slightly declined or remained constant, respectively, and the predominant localization of PCK mRNA in the periportal and intermediate zone was preserved. The present data suggest that the heterogeneous zonal activation of the PCK gene was essentially very similar in mouse, hamster and rat liver.

Zonal expression of the glucokinase gene in rat liver. Dynamics during the daily feeding rhythm and starvation-refeeding cycle demonstrated by in situ hybridization

The abundance and zonal distribution of glucokinase (GK) mRNA were studied in rat liver during a normal 12 h day/12 h night rhythm (dark from 1900 to 0700 hours) and during refeeding after 60 h of starvation. Zonation of GK gene expression was examined by in situ hybridization with a radiolabelled cRNA probe and GK mRNA abundance was determined by Northern blot analysis with a digoxigenin-labelled cRNA probe. GK mRNA appeared to be almost homogeneously distributed throughout the whole daily feeding cycle; yet it was predominantly localized in the perivenous and intermediate zone during refeeding after 60 h of starvation. During the daily feeding rhythm, the total amount of GK mRNA increased quickly with the beginning of the feeding period at 1900 hours reaching a maximum at midnight and then decreased continuously to a basal level at noon. Virtually no GK mRNA was detected after 60 h of starvation. Refeeding caused a rapid increase in GK mRNA to a maximum at 2400 hours followed by a decrease to approximately two-thirds of the maximum value at 0700 hours. If the homogeneous distribution of GK mRNA during the daily feeding rhythm was real rather than apparent because of too low a sensitivity of the cRNA probe, the present results suggest that during the normal circadian cycle the mainly perivenous distribution of GK enzyme activity and protein is regulated preferentially at a translational level. The findings clearly show that during refeeding after 60 h of starvation the GK distribution is controlled predominantly at a pretranslational level.