[The pulmonary function in scoliotic patient]

This paper investigated preoperative pulmonary functions in 134 scoliotic patients, of whom 32 cases was followed up for their postoperative pulmonary functions. The results show that the bigger the Cobb of the scoliosis, the greater the damages of the pulmonary functions. Congenital scoliosis is more severely affected by pulmonary functions than idiopathic scoliosis. There was no significant difference among the different sections of scoliosis with regard to their effect on the pulmonary functions. The authors concluded that the Harrington Instrumentation improved pulmonary functions in scoliosis.

Channel catfish, Ictalurus punctatus rafinesque, neutrophil adhesion to selected extracellular matrix proteins, lipopolysaccharide, and catfish serum

Adhesion of leukocytes to endothelium and extracellular matrix proteins is an important step in the inflammatory process. Therefore, the adhesion of channel catfish neutrophils to a surface coated with extracellular matrix proteins, LPS, and non-immune catfish serum was evaluated. Stimulation of neutrophils with phorbol dibutyrate (PDBU) resulted in at least two-fold increases in cellular adhesion to all substrates tested except laminin. When EDTA was included during or after PDBU stimulation, neutrophil adhesion to fibrinogen and LPS coated surfaces was reduced to the level of unstimulated neutrophils or to 50-60% of that for stimulated neutrophils. Similarly, EDTA and Ca2+/Mg2+ deficient medium reduced homotypic aggregation of PDBU stimulated neutrophils to background levels. Adhesion of stimulated neutrophils to fibrinogen coated surfaces was inhibited 44, 33, and 50% when soluble fibrinogen, fibronectin, and serum, respectively, were used to block the adhesion assay. The tripeptide integrin adhesion recognition sequence, Arg-Gly-Asp (RGD), caused 83% reduction and the fibrinogen-binding inhibitor protein caused 10% reduction in binding of stimulated neutrophils to fibrinogen coated surfaces. Two hexapeptides tested did not reduce neutrophil adhesion to fibrinogen. The binding of channel catfish neutrophils to the matrices used in the present study is suggestive that integrin mediated adhesion occurs during biological and pathological processes of teleosts.

1H, 15N and 13C resonance assignments and secondary structure of group II phospholipase A2 from Agkistrodon piscivorus piscivorus: presence of an amino-terminal helix in solution

1H, 15N and 13C resonance assignments are presented for the group II phospholipase A2 (PLA2) from Agkistrodon piscivorus piscivorus. The secondary structure of the enzyme has been inferred from an analysis of coupling constants, interproton distances, chemical shifts, and kinetics of amide exchange. Overall, the secondary structure of this PLA2 is similar to the crystal structure of the homologous group II human nonpancreatic secretory phospholipase [Scott, D.L., White, S.P., Browning, J.L., Rosa, J.J., Gelb, M.H. and Sigler, P.B. (1991) Science, 254, 1007-1010]. In the group I enzyme from porcine pancreas, the amino-terminal helix becomes fully ordered in the ternary complex of enzyme, lipid micelles and inhibitor. The formation of this helix is thought to be important for the increase in activity of phospholipases on aggregated substrates [Van den Berg, B., Tessari, M., Boelens, R., Dijkman, R., De Haas, G. H., Kaptein, R. and Verheij, H.M. (1995) Nature Strct. Biol., 2, 402-406]. However, the group II enzyme from Agkistrodon piscivorus piscivorus possesses a defined and well-positioned amino-terminal helix in the absence of substrate. Therefore, there is a clear difference between the conformation group I and group II enzymes in solution. These conformational differences suggest that formation of the amino-terminal helix is a necessary, but not sufficient, step in interfacial activation of phospholipases.

[Selective embolization of coronary vein of the stomach--a new approach for the treatment of bleeding from esophageal varices]

Selective embolization of coronary vein of stomach was employed for the treatment of 222 patients with bleeding from esophageal varices due to portal hypertension. The coronary vein was separated at middle segment and tube was inserted and clamped 5 cm below and above the cardia. The gamma-octyl-cyanoacrylate was used for embolization. 19 patients received preventive operation, 106 was subject to emergency surgery and 98 patients was treated by elective operation. The bleeding of all patients receiving emergency procedure was stopped. 3 died of liver failure after operation. 219 survived. 189 cases were followed up for 1-2 years and on varices was found. 182 cases followed up for 6 years revealed no relapse of bleeding. This technique could achieve good curative effect, which provides a new approach for the treatment of bleeding from esophageal varices of portal hypertension.

Chimeric GABAA/glycine receptors: expression and barbiturate pharmacology

GABAA and glycine receptors are close relatives in the "gene superfamily" of ligand-gated ion channels, but have distinctly different pharmacology. For example, barbiturates have two effects on GABAA receptors (GABAA-R): at low micromolar concentrations (2-5 microM), the anesthetic barbiturate methohexital potentiates submaximal chloride current responses to GABA; at higher concentrations (20-50 microM), the barbiturate causes direct gating of the channel in the absence of agonist. Neither of these barbiturate effects is seen on the glycine receptor (Gly-R). In order to study the structural parts of the GABAA-R involved in this barbiturate pharmacology, two unique restriction sites were introduced into the cDNAs encoding the alpha 2 and beta 1 subunits of the human GABAA-R and the alpha 1 subunit of the human gly-R. The first site ('X') corresponded to the C-terminal end of the third transmembrane domain (M3) in each subunit and enabled exchange of C-terminal fragment of approximately 100 amino acids (which includes the large 'cytoplasmic loop' and M4 segment) between GABAA-R and Gly-R subunits. The second site ('S') was approximately 30 amino acids 3'- from the N-terminal end of each subunit and enabled exchange of a small N-terminal fragment between GABAA-R and Gly-R subunits. Several chimeric receptor subunit cDNAs were constructed and the resulting receptors tested for their ability to respond to GABA and glycine and for sensitivity to the barbiturate methohextial (MTX). The results show that neither the large C-terminal fragment nor the smaller N-terminal fragment is associated with the enhancement or direct activation of the GABAA-R by MTX. These results demonstrate the viability of chimeric GABAA/Gly-R and suggest that the method will be suitable for further investigation of the molecular basis of the barbiturate pharmacology of the GABA-R.

Autoantibodies from patients with primary biliary cirrhosis recognize a region within the nucleoplasmic domain of inner nuclear membrane protein LBR

Autoantibodies from rare patients with primary biliary cirrhosis (PBC) recognize LBR, or lamin B receptor, an integral membrane protein of the inner nuclear membrane. Human LBR has a nucleoplasmic, amino-terminal domain of 208 amino acids followed by a carboxyl-terminal domain with eight putative transmembrane segments. Autoantibodies against LBR from four patients with PBC recognized the nucleoplasmic, amino-terminal domain but not the carboxyl-terminal domain. Immunoblotting of smaller fusion proteins demonstrated that these autoantibodies recognized a conformational epitope(s) contained within the stretch of amino acids from 1 to 60. These results, combined with those of previous studies, show that autoepitopes of nuclear membrane proteins are located within their nucleocytoplasmic domains and that autoantibodies from patients with PBC predominantly react with one domain of a protein antigen. This work also provides further characterization of anti-LBR antibodies that have found utility as reagents in cell biology research.

Anatomy of vasculature of 850 spleen specimens and its application in partial splenectomy

BACKGROUND

Anatomic knowledge of vasculature of the splenic lobe and segment is of great clinical significance in partial resections and transplantation of the spleen.

METHODS

The methods of two-colored corrosion casting, roentgenography, and anatomic dissection were used to evaluate the vasculature of the splenic hilum and intraspleen. On this basis splenic lobectomy and segmentectomy were performed on 42 patients with traumatized spleens.

RESULTS

In the observation of 850 spleen specimens the spleen showed a single lobar artery in 7 cases (0.8%), two lobar arteries in 730 cases (86%), three lobar arteries in 104 cases (12.2%), and multiple lobar arteries (i.e., more than three lobar arteries) in 9 cases (1%). In a subgroup of 276 specimens 17%, 53%, 24%, 4%, 1%, and 1% of spleen specimens had three, four, five, six, seven, and eight segmental arteries, respectively. The result from a subgroup of 280 specimens indicated that mean percentages of the existence of the superior and inferior polar arteries and of the coexistence of both polar arteries were 31.3%, 38.8%, and 13.3%, respectively. Relative avascular planes between segments or lobes were seen. Basic steps of splenic lobectomy or segmentectomy include mobilization of the injured spleen, ligation of vessels in the lobe or segment, transection of the splenic parenchyma, and sutures of the cut surface of the remaining spleen. The postoperative courses of all 42 patients undergoing partial splenectomy were uneventful. No postoperative bleeding and necrosis of the remaining spleen or infectious complications were registered.

CONCLUSIONS

Anatomically the spleen is defined with two primary lobes (the superior lobe and inferior lobe), one accessory lobe, and three to five segments. This new classification facilitates surgeons to perform partial resections of the spleen and allotransplantation of the hemispleen from a living related donor in human beings.

Demonstrations of de-and remineralization mechanism as revealed in synthetic auditory ossicle (Apaceram) of rats by laser-Raman spectrometry

In investigations of the process of bone destruction caused by chronic otitis media complicated with cholesteatoma, we proposed previously a hypothesis to explain its mechanism. In the present study, we substitute a synthetic auditory ossicle (Apaceram) for the bone to simplify the model system of experiments for our hypothesis. Its process was studied on a model simulation in vitro, in vivo and clinically at molecular level, using laser-Raman spectrometry. An increase of conductivity in both the saline solution and double-distilled water immersed Apaceram indicated demineralization depending on time lapse. The process of demineralization was revealed by the Raman spectral profiles as shown by narrowing a half-peak breadth (p < 0.01) of v1 signal (PO4(3-), 960 cm-1) and the disappearance of the shoulder at circa 950 cm-1 on the Apaceram surface implanted for 6 months. On the other hand, the process of remineralization was revealed in vivo by the spectral profiles: 1) a broader half-peak breadth (p < 0.01) of v1 signal on the Apaceram surface implanted for 10 months than that implanted for 6 months; 2) a weak reappearance of the shoulder at ca. 950 cm-1 on the Apaceram surface after 10 months; 3) four signals (v1 through v4) of PO4(3-) on the HOAP observed for inside the Apaceram shaft and 4) a weak v1 signal on both the granular fluorescent substance in the clinical case and the high density area of subcutaneous tissue after contact with the Apaceram in rats for 3 months. Judging from these investigations, it is proposed that the mechanism of bone destruction associated with cholesteatoma is a form of de- and remineralization.

[Surgical treatment of spinal tumors: a report of 30 cases]

With the advance of spinal surgery in the last decade, surgical treatment of spinal tumors has been no longer limited to sole laminectomy. The principles of surgical treatment of spinal tumors include: (1) anterior approach for the anterior lesion and posterior approach for the posterior lesion, (2) combined anterior and posterior approach for extensive lesions and (3) internal fixation for spinal stability. 30 cases of spinal tumors were treated on the basis of the above guiding principles and 83.3% (25 of 30 cases) showed excellent or good outcomes.

Longicin and goniothalamicinone: novel bioactive monotetrahydrofuran acetogenins from Asimina longifolia

Longicin [1] and (2,4-cis and trans)-goniothalamicinone [2], two new monotetrahydrofuran Annonaceous acetogenins, have been isolated from the leaves and twigs of Asimina longifolia (the long leaf paw paw) by the use of the brine shrimp lethality test for bioactivity-directed fractionation. The structures were elucidated based on spectroscopic and chemical methods. Compound 1 was converted to its ketolactone isomer, (2,4-cis and trans)-longicinone [3], to aid the stereochemical elucidation of 1. Compounds 1-3 showed selective and potent cytotoxicities to certain human tumor cell lines, with the potency of 1 against pancreatic carcinoma (PaCa-2) over one million times that of adriamycin. Nine known cytotoxic acetogenins, annonacin, xylomaticin, isoannonacin, gigantetrocins A and B, muricatetrocins A and B, gigantetrocin-A-one and goniothalamicin, were also isolated for the first time from this species.

Variable chimerism, graft-versus-host disease, and tolerance after different kinds of cell and whole organ transplantation from Lewis to brown Norway rats

The bidirectional paradigm of tolerance involving reciprocal host vs. graft and graft vs. host reactions was examined after Lewis (LEW)-->Brown Norway (BN) transplantation of different whole organs (liver, intestine, heart, and kidney) or of 2.5 x 10(8) LEW leukocytes obtained from bone marrow, spleen, lymph nodes, and thymus. The experiments were performed without immunosuppression or under 14 daily doses of postoperative tacrolimus, which were continued in weekly doses to 100 days in a "continuous treatment" subgroup, and to 27 days in a short treatment group. Without immunosuppression, all organs and cell suspensions failed to engraft or were acutely rejected. GVHD (usually fatal) was always caused when either the long or short treatment was used for recipients of intestinal grafts and cell suspensions of spleen and lymph nodes. In contrast, both immunosuppressive protocols allowed engraftment of bone marrow cells, liver, heart, and kidney without clinical GVHD, whereas thymus cell suspensions and small doses of whole blood neither engrafted nor caused GVHD. At 100 days, now drug-free for 73 days, the liver, bone marrow, and heart recipients were tolerant in that they accepted all challenge LEW heart and/or liver grafts for 100 more days despite in vitro evidence of donor-specific reactivity (split tolerance). At 200 days, histopathologic studies of the challenge livers were normal no matter what the priming graft. However, the still-beating challenge hearts had a spectrum from normal to severe chronic rejection that defined the tolerogenicity of the original primary grafts: liver best-->bone marrow next-->heart least. Both the GVHD propensity and tolerogenicity in these experiments were closely associated with recipient tissue chimerism 30 and 100 days after the experiments began. The tissue chimerism was invariably multilineage, but the GVHD outcome was associated with T cell over-representation. These observations provide guidelines that should be considered in devising leukocyte augmentation protocols for human whole organ recipients. The results are discussed in relation to the historical tolerance studies of Billingham, Brent, and Medawar; Good; Monaco; and Calne.

Protein-protein interactions between human nuclear lamins expressed in yeast

Protein-protein interactions between the nuclear lamins are responsible for the assembly of the nuclear lamina, a meshwork of intermediate filaments associated with the nuclear envelope inner membrane. We have used the yeast two-hybrid system to examine the interactions between the predominant human nuclear lamins expressed as GAL4 fusion proteins in Saccharomyces cerevisiae. Lamin A, prelamin A, lamin B1, and lamin C were able to form homodimers as well as heterodimers. Analysis of the different structural domains of lamin B1 demonstrated that the second half of coil 2 of the rod domain was necessary for the formation of the most stable homodimers. The results show that the yeast two-hybrid system can be used to study the interactions between structural proteins and their domains.

Simple aromatics identified with a NFAT-lacZ transcription assay for the detection of immunosuppressants

Determination of the mechanism of action of FK506 and cyclosporin A has yielded new molecular targets involved in signal transduction during T cell activation. A common target of FK506 and cyclosporin A is inhibition of activation of the NFAT transcription factor, for which a specific binding region is present in the promoter of the IL-2 gene. A reporter gene assay has been used to screen for agents that interfere with this early step in T cell activation. Simple aromatic compounds that block NFAT-dependent transcription and show in vitro immunosuppressive activity were isolated from the broth and mycelia of two Streptomyces sp. fermentations. The compounds were active at concentrations that were not directly cytotoxic.

Hamster to rat kidney xenotransplantation. Effects of FK 506, cyclophosphamide, organ perfusion, and complement inhibition

Hamster to rat renal xenotransplantation was performed with recipient nephrectomies. Recipients were treated beginning on day 0 with continuous FK 506 monotherapy, a 7-day or open-ended monotherapeutic course of cyclophosphamide (CP), and the two drug regimens combined. CP alone (10 mg/kg/day) prevented a xenospecific antibody response and tripled median survival of the kidney (defined as recipient death) from 6 (control) to 18.5 days whereas FK 506 alone had no effect. The drugs in combination were no better than CP alone (15 days) unless the 5-day course of CP was given at a higher dose (15 mg/kg) and started 3 days preoperatively (79 days). In further experiments, adjuvant measures were added to the minimally effective FK 506/7-day CP regimen which gave a median survival of only 15 days. In the most successful modification, intraoperative antibody depletion by the temporary transplantation of third party hamster liver or en bloc kidneys increased median survival from 15 to 34 and 48 days, respectively. An intraoperative i.v. dose administration of the anticomplement drug K76 instead of antibody depletion increased survival to 26 days. Although the events of kidney rejection were similar to those of heart xenografts and partially forestalled by the antibody inhibiting CP treatment, or by antibody depletion, survival for > 100 days was accomplished in only 5 of 86 treated animals. The poorer survival previously reported with cardiac xenotransplantation is largely explained by the life support requirement of the kidneys. Renal failure was responsible for almost all deaths before 60 days, and subnormal renal failure was a pervasive adverse factor thereafter, frequently caused by pyelonephritis which is suspected to have had an immunologic etiology.

[Patella resurfacing and patellofemoral resurfacing]

Since 1983 isolated polyethylene patellar prosthesis was used for patella resurfacing of 19 patients with patellofemoral osteoarthritis. After an average of 44.9 months follow-up, the treatment was found to be not as satisfactory as earlier trials. The main reason was the wide erosion of femoral condyle caused by the polyethylene patella. To overcome this shortness, a new type of patellofemoral prosthesis was designed by the authors, which was named Y-L-Q. From January, 1991 to November, 1993, this prosthesis was used to treat 16 knees of 13 patients with patellofemoral osteoarthritis. Most of those patients improved both symptomatically and functionally. The good to excellent results rate was 87.5% (14/16 knees) at the time of an average 10 month follow-up. The early results of our experience with patellofemoral resurfacing are encouraging, and extended follow-ups are in progress.

Patella and patellofemoral resurfacing (37 cases report)

Chondromalacia and patellofemoral osteoarthritis are common diseases that cause pain and disablement of the knee. Conservative therapy is not always effective. Since 1983 we have used isolated polyethylene patellar prosthesis for patella resurfacing of 19 patients with patellofemoral osteoarthritis. After an average of 44.9 months follow-up, we found the treatment was not as satisfactory as earlier trials. The main reason is the wide erosion of femoral condyle caused by the polyethylene patella. To overcome this shortness, we designed a new type of patellofemoral prosthesis which is named Y-L-Q. From January, 1991 to November, 1993, we used this prosthesis to treat 16 knees of 13 patients with patellofemoral osteoarthritis. Most of those patients improved both symptomatically and functionally. The good to excellent results rate was 87.5% (14/16 knees) at the time of an average 16 months follow-up. The early results of our experience with patellofemoral resurfacing are encouraging, and extended follow-ups are in progress.

Effects of voltage perturbation of the lingual receptive field on chorda tympani responses to Na+ and K+ salts in the rat: implications for gustatory transduction

Taste sensory responses from the chorda tympani nerve of the rat were recorded with the lingual receptive field under current or voltage clamp. Consistent with previous results (Ye, Q., G. L. Heck, and J. A. DeSimone. 1993. Journal of Neurophysiology. 70:167-178), responses to NaCl were highly sensitive to lingual voltage clamp condition. This can be attributed to changes in the electrochemical driving force for Na+ ions through apical membrane transducer channels in taste cells. In contrast, responses to KCl over the concentration range 50-500 mM were insensitive to the voltage clamp condition of the receptive field. These results indicate the absence of K+ conductances comparable to those for Na+ in the apical membranes of taste cells. This was supported by the strong anion dependence of K salt responses. At zero current clamp, the potassium gluconate (KGlu) threshold was > 250 mM, and onset kinetics were slow (12 s to reach half-maximal response). Faster onset kinetics and larger responses to KGlu occurred at negative voltage clamp (-50 mV). This indicates that when K+ ion is transported as a current, and thereby uncoupled from gluconate mobility, its rate of delivery to the K+ taste transducer increases. Analysis of conductances shows that the paracellular pathway in the lingual epithelium is 28 times more permeable to KCl than to KGlu. Responses to KGlu under negative voltage clamp were not affected by agents that are K+ channel blockers in other systems. The results indicate that K salt taste transduction is under paracellular diffusion control, which limits chemoreception efficiency. We conclude that rat K salt taste occurs by means of a subtight junctional transducer for K+ ions with access limited by anion mobility. The data suggest that this transducer is not cation selective which also accounts for the voltage and amiloride insensitive part of the response to NaCl.

[Modified en bloc resection procedure for malignant tumor of the shoulder girdle]

En bloc resection of the shoulder girdle (Tikhoff-Linberg procedure) is a valuable limb-sparing surgical technique for bony and soft tissue malignant tumor in and around the proximal humerus and shoulder girdle. Significant amount of hand-elbow function is maintained with the procedure, and long time results in the treatment of neoplasms by this technique was found to be the same as by the method of a forequarter amputation or the shoulder disarticulation in the English literature. Four cases with malignant tumor in the shoulder girdle was treated with this modified method in our department. The average follow-up was 8 years. One case died due to another kind of tumor 6 years after operation, and other 3 cases are alive and disease free.

Application of internal fixation in the treatment for tuberculosis of the spine

This is a study of 18 patients who had surgical treatment for spinal tuberculosis. All patients were admitted with the spinal tuberculosis and treated with a combination of anterior debridement and bone graft with posterior internal fixation using the Luque or Dick technique. The patients were able to walk within a few days postoperation. Three to seven years follow-ups show no recurrence, kyphosis and/or solid fusion.

Intracellular Ca2+ and Ca(2+)-binding proteins in chemically transformed rat fibroblasts

Disturbed Ca2+ handling and altered levels of Ca(2+)-binding proteins (CaBPs) have been found in many transformed cells. To investigate whether there exists a correlation between expression of CaBPs and intracellular Ca2+ we analyzed three transformed rat fibroblast cell lines (T14, T10, and T43) exhibiting different levels of CaBPs. All three cell lines express calmodulin (CaM) at elevated levels compared to normal tissues. In addition, oncomodulin (OM) is expressed at high levels in T14 cells and at much lower levels in T10 cells, while T43 cells do not express OM. We demonstrate that CaBP levels are affected by changes of extracellular [Ca2+] ([Ca2+]o). In reduced [Ca2+]o, CaM levels were increased up to 60%, while OM levels were decreased up to 65% in T14 and T10 cells. Increase of [Ca2+]o, on the other hand, led to a decrease of CaM levels and an increase of OM levels, suggesting that [Ca2+]o exerts its effect on OM and CaM differently. Comparison of the growth rates in reduced [Ca2+]o revealed that T14 cells with the most pronounced CaM increase induced by low [Ca2+]o grew best under these conditions. These results indicate that elevated CaM expression but not the presence of OM reduces the Ca2+ requirement for growth. Intracellular [Ca2+] transients are not buffered by the high concentration of CaBPs in T14 cells. In contrast, [Ca2+]i transients induced by increase of [Ca2+]o or addition of serum were most pronounced in T14 cells compared to T10 and T43 cells.

[Long-term follow-up of patients with patella resurfacing]

Patellar resurfacing was performed by the authors. From 1983 to 1988, 19 cases (22 knees) with patello-femoral osteoarthritis were treated with this procedure in our hospital. Excellent and good results were recorded in 13 cases (59.1%) one year after operation, but were zero in the long-term follow-up (average 8.7 years) because of recurrent knee pain due to the wearing of the cortex of the femoral groove. Further operation was necessary for those cases, such as patellectomy or total knee replacement. Since 1991 Y-L-Q's type of patellofemoral replacement has been used in 11 cases in our department to alter the isolated resurfacing of the patella. The femoral groove was replaced with a metallic implant that allows sliding of a polyethylene patella to prevent the wearing of the femoral cortex. Preliminary results are good.

[The use of internal fixation in the treatment of spinal tuberculosis]

We have applied debridement with grafting and internal fixation techniques (including Luque and Dick procedures) in the treatment of tuberculosis of the spine in the past few years. Analysis of 18 patients showed good prognosis after the Luque or Dick procedure. The patients are able to walk around within a few days after operation. One to five years of follow-up showed no recurrence or kyphotic deformity.

[The prevention and treatment of complications with pedicle screws]

Pedicle screws are more commonly used by spinal surgeons recently. Although Roy-Camile, Dick, Steffee, R-F etc., are all different surgical procedures, all need pedicle screw techniques. Up to March 1991, 61 cases with 334 screws inserted by Steffee and Dick operations had been performed in our hospital. Neurological symptoms, among all complications, are the most serious problems associated with these procedures. By analyzing the insertion point, transverse screw angle, sagittal angle and other causes of complications of pedicle screws, we present here our experiences for prevention and treatment of these complications.

Primary structure analysis and lamin B and DNA binding of human LBR, an integral protein of the nuclear envelope inner membrane

We have determined the primary structure of human LBR, an integral protein of the nuclear envelope inner membrane, and examined its interactions with lamin B and DNA. Human LBR is 68% identical to the chicken lamin B receptor and has a basic nucleoplasmic amino-terminal domain of 208 amino acids followed by a hydrophobic domain with eight putative transmembrane segments. The amino-terminal domain contains a Ser-Arg-rich stretch and consensus sites for phosphorylation by protein kinase A and p34cdc2 protein kinase. A fusion protein containing the amino-terminal domain of human LBR is recognized by autoantibodies from patients with primary biliary cirrhosis, and these serum antibodies label the nuclear envelope when examined by immunofluorescence microscopy. The LBR amino-terminal domain precipitates lamin B from nuclear extracts and retards the migration of double-stranded DNA subjected to agarose gel electrophoresis. When immobilized on nitrocellulose, the amino-terminal domain of LBR also associates with DNA, and the stretch between amino acids 71 and 100, which contains the Ser-Arg-rich stretch, is necessary for DNA binding. These results demonstrate that LBR is conserved among vertebrate species and that its nucleoplasmic domain can potentially mediate the interaction of both the nuclear lamina and the chromatin with the inner nuclear membrane.

Dietary Na(+)-restriction prevents development of functional Na+ channels in taste cell apical membranes: proof by in vivo membrane voltage perturbation

1. Chorda tympani (CT) neural responses to NaCl were recorded while the potential across the apical membrane of taste cells was perturbed by voltage clamp in rats fed a Na(+)-restricted diet pre- and postnatally (Na(+)-restricted rats) and in controls. 2. Control rats gave CT responses that were enhanced at negative voltage clamp and suppressed at positive voltage clamp. In contrast, CT responses from Na(+)-restricted rats were virtually voltage insensitive. 3. Analysis of the voltage-sensitivity of the CT response shows that Na(+)-restricted rats have < 10% of the density of functional apical Na+ channels normally present in control rats demonstrating that early dietary Na(+)-restriction prevents the functional expression of these key elements in salt taste transduction. Furthermore, the data demonstrate the value of this technique in assessing involvement of distinct cellular domains in taste transduction.

Application of Steffee operation in spinal surgery

Steffee operation is a surgical method of internal fixation for unstable conditions of the spine. Up to March 1991, 32 cases of various spine disorders were treated with the Steffee system in our hospital. These operations brought good results, as 83.4% of the cases received either good or excellent functional and clinical ratings postoperatively. Among patients with spondylolisthesis, the degree of slip correction averaged 58.5% postoperatively. Neurological complications are avoided by accurate localization of the screws.

Voltage dependence of the rat chorda tympani response to Na+ salts: implications for the functional organization of taste receptor cells

1. Voltage-clamp and current-clamp data were obtained from a circumscribed region of the anterior rat lingual epithelium while simultaneously monitoring the afferent, stimulus-evoked, neural response from the same receptive field. 2. Chorda tympani (CT) responses at constant Na(+)-salt concentration were enhanced by submucosa negative voltage clamp and suppressed by positive voltage clamp. The complete CT response profile, including the time course of adaptation, was not uniquely determined by NaCl concentration alone. The response could be reproduced at different NaCl concentrations by applying a compensating voltage. 3. The form of the concentration and voltage dependence of the CT response indicates that the complete stimulus energy is the Na+ electrochemical potential difference across receptor cell apical membranes, and not Na+ concentration alone. This is the underlying principal behind the equivalence of chemical and electric taste for Na+ salts. 4. CT responses to sodium gluconate (25 and 200 mM) and 25 mM NaCl produced amiloride-insensitive components (AIC) of low magnitude. NaCl at 200 mM produced a significantly larger AIC. The AIC was voltage-clamp independent. The relative magnitude of the AIC was positively correlated with the transepithelial conductance of each salt. This suggests that the large AIC for 200 mM NaCl results from its relatively high permeability through the paracellular pathway. 5. Analysis of the CT response under voltage clamp revealed two anion effects on Na(+)-salt taste, both of which act through the paracellular shunt. 1) Anions modify the transepithelial potential (TP) across tight junctions and thereby modulate the cell receptor potential. This anion effect can be eliminated by voltage clamping the TP. 2) Sufficiently mobile anions facilitate electroneutral diffusion of Na+ salts through tight junctions. This effect is observed especially when Cl- is the anion and when the stimulus concentration favors NaCl influx, allowing Na+ to stimulate receptor cells from the submucosal side. Because the submucosal intercellular spaces are nearly isopotential regions, this effect is insensitive to voltage clamp of the TP. The large AIC associated with this anion effect is due to the low permeability of amiloride.

[The application of Dick instrumentation in the field of spine surgery]

From June, 1989 to March, 1991, 24 cases were treated in our department with the Dick technique. The study population included 7 patients with fresh horacolumber spine fracture, 10 with late spinal fracture (15 of the above 17 cases had incomplete paraplegia), 3 with ankylosing spondylitis, 2 with tuberculosis, and one each with spondylolisthesis and spine tumor. The results of these 24 cases were as follows. In the fresh fracture group, all the spine fractures were reduced completely. The 2 patients without neurological defects returned to work 3 months after operation. The 3 with incomplete paraplegia had rapid neurological recovery and could walk with a brace 3 months after surgical treatment. The 2 with complete paraplegia did not recover after toperation. In the late fracture group, traumatic kyphotic curve were reduced partially and back pain was decreased markedly in all 10 cases. Muscular power was increased significantly in 3 cases; they are all able to walk with a cane. Spasticity was remarkably improved in 2 patients after operation; they can now walk with crutches. Three patients obtained complete cure of incontinence. Four patients had no significant improvement. In the 3 patients with ankylosing spondylitis, the initial average kyphotic curve was 73.3 degrees, while the postoperative average curve was 28.3 degrees. The result in treating spinal stenosis due to degenerative spondylolisthesis was good: the slipping vertebrae were stabilized and fused with the Dick system after thorough decompression. In the tumor and Tb-spine cases, the patients recovered and were ambulatory soon after operation, thanks to rigid internal fixation.

Effects of the anesthetic dibucaine on the kinetics of the gel-liquid crystalline transition of dipalmitoylphosphatidylcholine multilamellar vesicles

The effects of the anesthetic dibucaine on the relaxation kinetics of the gel-liquid crystalline transition of dipalmitoylphosphatidylcholine (DC16PC) multilamellar vesicles have been investigated using volume-perturbation calorimetry. The temperature and pressure responses to a periodic volume perturbation were measured in real time. Data collected in the time domain were subsequently converted into and analyzed in the frequency domain using Fourier series representations of the perturbation and response functions. The Laplace transform of the classical Kolmogorov-Avrami kinetic relation was employed to describe the relaxation dynamics in the frequency domain. The relaxation time of anesthetic-lipid mixtures, as a function of the fractional degree of melting, appears to be qualitatively similar to that of pure lipid systems, with a pronounced maximum, tau max, observed at a temperature corresponding to greater than 75% melting. The tau max decreases by a factor of approximately 2 as the nominal anesthetic/lipid mole ratio increases from 0 to 0.013 and exhibits no further change as the nominal anesthetic/lipid mole ratio is increased. However, the fractional dimensionality of the relaxation process decreases monotonically from slightly less than two to approximately one as the anesthetic/lipid mole ratio increases from 0 to 0.027. At higher ratios, the dimensionality appears to be less than one. These results are interpreted in terms of the classical kinetic theory and related to those obtained from Monte Carlo simulations. Specifically, low concentrations of dibucaine appear to reduce the average cluster size and cause the fluctuating lipid clusters to become more ramified. At the highest concentration of dibucaine, where n < 1, the system must be kinetically heterogeneous.

The application of Dick instrumentation in spine surgery

From June, 1989 to March, 1991, 24 cases with various spinal disorders were treated in our department using the Dick technique. The results were as follows: In the fresh fracture group (7 cases), all the spine fractures were reduced anatomically: the 2 cases without neurological defects returned to work 3 months after operation; the 3 cases with incomplete paraplegia had rapid neurological recovery; and the 2 cases with complete paraplegia showed no recovery after operation. In the late fracture group (10 cases), traumatic kyphotic curves were partially reduced and back pain was decreased markedly in all: Muscle power was increased significantly in 3 cases; spasticity was remarkably improved in 2 cases; 3 cases obtained complete cure of incontinence; and 4 cases had no significant improvement. In 3 cases with ankylosing spondylitis, the initial average kyphotic curve was 73.3 degrees, while the postoperative average curve was 28.3 degrees. The result of treatment of spinal stenosis due to degenerative spondylolisthesis (1 case) was good; slipping vertebrae were stabilized and fused with the Dick system after thorough decompression. In 1 tumor and 2 Tb-spine cases, the patients recovered and were ambulatory soon after operation.

Gel-liquid crystalline transition of some multilamellar lipid bilayers follows classical kinetics with a fractional dimensionality of approximately two

The relaxation kinetics of the gel-liquid crystalline transition of phosphatidylcholine (DC14PC, DC16PC, and DC18PC) multilamellar vesicles have been examined using volume-perturbation calorimetry. The time-dependent temperature and pressure changes associated with a periodic volume perturbation are monitored in real time. Data collected in the time domain are transformed to the frequency domain using Fourier series representations of the perturbation and response functions. Because a very small perturbation is imposed during the experiment, linear response theory is suitable for analysis of the relaxation process. The Laplace transform of the classical Kolmogorov-Avrami relation of transition kinetics is used to describe the dynamic response in the frequency domain. For DC14PC and DC16PC, the relaxation process is better fit with an effective dimensionality of n = 2 rather than n = 1. For DC18PC, we estimate that an effective dimensionality of approximately 1.5 will best fit the data. These results indicate that the gel-liquid crystalline transition of these lipid bilayers follows the classical Kolmogorov-Avrami kinetic model with an effective dimensionality greater than 1 and the assumption of simple exponential decay (n = 1) commonly used in data analysis may not always be valid for lipid transitions. Insofar as the dimensionality of the relaxation reflects the geometry of fluctuating lipid clusters, this parameter may be useful in connecting experimental thermodynamic and kinetic results with those obtained from Monte Carlo simulations.

The anion paradox in sodium taste reception: resolution by voltage-clamp studies

Sodium salts are potent taste stimuli, but their effectiveness is markedly dependent on the anion, with chloride yielding the greatest response. The cellular mechanisms that mediate this phenomenon are not known. This "anion paradox" has been resolved by considering the field potential that is generated by restricted electrodiffusion of the anion through paracellular shunts between taste-bud cells. Neural responses to sodium chloride, sodium acetate, and sodium gluconate were studied while the field potential was voltage-clamped. Clamping at electronegative values eliminated the anion effect, whereas clamping at electropositive potentials exaggerated it. Thus, field potentials across the lingual epithelium modulate taste reception, indicating that the functional unit of taste reception includes the taste cell and its paracellular microenvironment.

Relaxation dynamics of the gel to liquid-crystalline transition of phosphatidylcholine bilayers. Effects of chainlength and vesicle size

The relaxation kinetics of the gel to liquid-crystalline transition of five phosphatidylcholine (DC14PC to DC18PC) bilayer dispersions have been investigated using volume perturbation calorimetry, a steady-state technique which subjects a sample to sinusoidal changes in volume. Temperature and pressure responses to the volume perturbation are measured to monitor the relaxation to a new equilibrium position. The amplitude demodulation and phase shift of these observables are analyzed with respect to the perturbation frequency to yield relaxation times and amplitudes. In the limit of low perturbation frequency, the temperature and pressure responses are proportional to the equilibrium excess heat capacity and bulk modulus, respectively. At all temperatures, the thermal response data are consistent with a single primary relaxation process of the lipid. The less accurate bulk modulus data exhibit two relaxation times, but it is not clear whether they reflect lipid processes or are characteristic of the instrument. The observed thermal relaxation behavior of all multilamellar vesicles are quantitatively similar. The relaxation times vary from approximately 50 ms to 4 s, with a pronounced maximum at a temperature just greater than Tm, the temperature of the excess heat capacity maximum. Large unilamellar vesicles also exhibit a single relaxation process, but without a pronounced maximum in the relaxation time. Their relaxation time is approximately 80 ms over most of the transition range.

Investigation of an outbreak of adult diarrhea rotavirus in China

In 1987 an epidemic of diarrhea associated with adult diarrhea rotavirus (ADRV) occurred in Qinhuangdao City, China, affecting more than 200 persons and causing 2 deaths. The outbreak was introduced by a person returning from an epidemic area and was spread initially to his family members and subsequently to the entire community. Adults were at greater risk of diarrhea than children 0-4 y of age and, the duration of illness increased significantly with increasing age. ADRV was identified by ELISA and electron microscopy. The electropherotypes of all positive specimens were identical, consistent with the single point-source introduction of the virus. Seroconversion was detected in 6 of 7 ill persons with a blocking ELISA. Both asymptomatic infection and person-to-person spread identified in this epidemic suggest that current emphasis on preventing waterborne transmission may not control the introduction of ADRV into new areas. The predisposition of adults for more severe disease with ADRV is similar to the pattern observed with other enteric viruses such as the Norwalk agent and hepatitis A.

Conformational and steric aspects of phenylethanolamine and phenylethylamine analogues as substrates or inhibitors of phenylethanolamine N-methyltransferase

The conformational and steric aspects of binding to phenylethanolamine N-methyltransferase (PNMT; EC 2.1.1.28) for phenylethanolamine substrates and phenylethylamine inhibitors were probed with three conformationally defined analogues (11, 12, and 13) of phenylethylamine (1) and phenylethanolamine (6) containing the benzobicyclo[3.2.1]octane skeleton. The 2-aminotetralin (2AT) moiety in conformationally defined analogues 11, 12, and 13 exists in a half-chair conformation with an equatorial amino group. Although conformationally restricted phenylethylamine analogue 2AT (3, Ki = 6.8 microM) and conformationally restricted phenylethanolamine analogues (cis)- and (trans)-2-amino-1-tetralol (9, Km = 22 microM; Vmax = 0.15; 100 X Vmax/Km = 0.68; 10, Ki = 9.4 microM) are good ligands for PNMT, none of the analogues 11, 12, and 13 showed activity as a substrate of PNMT. The fact that 11 (Ki = 206 microM) is more potent than analogues 4 (Ki = 1296 microM) and 5 (Ki = 479 microM), with a half-boat 2AT moiety, suggests that PNMT preferentially binds the half-chair conformation of 2AT at the active site. This is consistent with previous findings that a fully extended conformation for the aminoethyl side chain of phenylethylamine inhibitors is optimal for PNMT binding. The reduced activity of 11, 12 (Ki = 1246 microM), and 13 (Ki = 3000 microM), compared with 2AT and (cis)- and (trans)-2-amino-1-tetralol (9 and 10) is consistent with a negative steric interference from the extra ethano bridge in 11, 12, and 13. The results from 11, 12, and 13, combined with previous findings, suggest that PNMT interacts better with relatively planar ligands.

Conformational requirements of substrates for activity with phenylethanolamine N-methyltransferase

beta-Phenylethanolamines have long been known to be substrates for the enzyme that converts norepinephrine to epinephrine (phenylethanolamine N-methyltransferase, PNMT, EC 2.1.1.28). In an effort to determine which, if any, particular conformation of the aminoethyl side chain of phenylethanolamines is required for PNMT active site binding and catalysis, we have prepared and evaluated conformationally restricted phenylethanolamine analogues 8-10. The folded phenylethanolamine derivative 4-hydroxy-1,2,3,4-tetrahydroisoquinoline (8) is not a substrate and does not interact with the enzyme active site as an inhibitor as well as 1,2,3,4-tetrahydroisoquinoline (6). In the cyclic 2-aminotetralol systems, only cis-phenylethanolamine derivative 9 demonstrates activity as a PNMT substrate. The corresponding trans isomer 10 is not a substrate, in spite of enhanced active site interactions with respect to the parent analogue (2-aminotetralin, 4). Comparison of the inhibition constants for the folded (8,Ki = 175 microM) and extended (10,Ki = 9 microM) phenylethanolamine analogues strongly suggests that simultaneous binding of both the amino and hydroxyl functionalities to the PNMT active site requires an extended aminoethyl side chain conformation.