Expression of HBV Pre S1 peptide in E. coli and product characterization

HBV Pre S1 sequence is supposed to play an important role in the infection of HBV. Presence of Pre S1/anti-Pre S1 in serum has valuable clinical implications. In order to improve the study of Pre S1, Pre S1 sequence was overexpressed in E. coli as a fusion protein with MBP (Maltose-binding protein), and anti-Pre S1 antiserum was elicited in rabbits by Pre S1-MBP purified by affinity chromatography. The recombinant plasmid constructed from pMAL-cRI expressed the 106aa Pre S1 sequence at the C terminal of MBP by tac promoter. The resulting protein is about 54 kD in size. Western-blot analysis confirmed its reactivity with antiserum derived from synthetic Pre S1 peptide and serum from patients with acute hepatitis B (AHB). ELISA showed that Pre S1-MBP and Dane particles purified from AHB patient's serum reacted with antiserum against synthetic Pre S1 peptide, and this reaction was specifically inhibited by synthetic Pre S1 peptide. ELISA also demonstrated that antiserum against Pre S1-MBP reacted with synthetic Pre S1 peptide, but not with synthetic HCV peptide or HEV peptide.

[Comparative test on spawn culture materials of Poria cocos]

It saves much time, work and timber when Poria cocos spawn is made from cottonseed hulls and pine sawdust. Compared with the yields from pine wood chip, the difference is not significant.

Active site-directed double mutants of dihydrofolate reductase

Variants of dihydrofolate reductase (DHFR), which confer resistance to antifolates, are used as dominant selectable markers in vitro and in vivo and may be useful in the context of gene therapy. To identify improved mutant human DHFRs with increased catalytic efficiency and decreased binding to methotrexate, we constructed by site-directed mutagenesis four variants with substitutions at both Leu22 and Phe31 (i.e., Phe22-Ser31, Tyr22-Ser31, Phe22-Gly31, and Tyr22-Gly31). Antifolate resistance has been observed previously when individual changes are made at these active-site residues. Substrate and antifolate binding properties of these "double" mutants revealed that each have greatly diminished affinity for antifolates (> 10,000-fold) yet only slightly reduced substrate affinity. Comparison of in vitro measured properties with those of single-residue variants indicates that double mutants are indeed significantly superior. This was verified for one of the double mutants that provided high-level methotrexate resistance following retrovirus-mediated gene transfer in NIH3T3 cells.

Diagnosis of hepatitis C Virus (HCV) infection by antigen-capturing ELISA

BACKGROUND

Hepatitis C virus (HCV) is a major cause of non-A non-B hepatitis. Detection of circulating antibodies against HCV by enzyme-linked immunosorbent assay (ELISA) has provided the main approach for the diagnosis of HCV infection. Most ELISA kits use a mixture of core, NS3, NS4 and NS5 antigen as capture antigens and enzyme-labeled goat anti-human IgG as conjugate.

OBJECTIVES

To establish an ELISA system based on the antigen-capturing principle, using a recombinant chimeric polyprotein containing four HCV antigenic components as antigen.

STUDY DESIGN

HCV antigens were expressed in Escherichia coli as chimeric polyprotein either in inclusion bodies or in soluble form. Protein expressed in inclusion bodies was used as solid-phase antigen, and the antigen expressed in a soluble form was used as enzyme conjugate after being labeled with horseradish peroxidase (HRP).

RESULTS

Genes coding HCV antigens were cloned and sequenced, chimeric polyproteins containing four immunodominant components (core, NS3, NS4 and NS5) were expressed in E. coli both in soluble and in inclusion body form. These two chimeric proteins retained the antigenicity of HCV antigens. Antibody-capturing ELISA using the chimeric antigens showed a sensitivity of 97% (97/100) and a specificity of 98% (97/99) using the reference panel from the National Institute for the Control of Pharmaceutic and Biological Products of China (NICPBC); the same assay showed a sensitivity of 97.9% (48/49) and a specificity of 100% (43/43) using the self-established reference panel. Antigen-capturing ELISA was set up using the antigen labeled with horseradish peroxidase as conjugate, and was shown to be as sensitive as (97.9%) and more specific than (100%) antibody-capturing ELISA using the reference panel in this work. The antigen-capturing ELISA also showed a high accordance (98.9%) with UBI HCV enzyme immunoassay (EIA) 4.0 kits (United Biomedical Inc. USA).

CONCLUSION

Antigen-capturing ELISA provided a convenient, sensitive and more specific approach for the diagnosis of hepatitis C virus infection.

The weaver mutation changes the ion selectivity of the affected inwardly rectifying potassium channel GIRK2

The weaver mutation in mice has recently been identified as a single base-pair mutation in the Girk2 gene, which encodes a G-protein-activated inwardly rectifying potassium channel, GIRK2. The mutation results in a Gly to Ser substitution at residue 156, in the putative pore-forming region of the potassium channel. In the present study, we used Xenopus oocytes to express mutant GIRK2, and to characterize the effects of the mutation on the channel. The mutation results in a loss of the normal high selectivity for K+ over Na+, with little effect on other channel properties such as activation by the mu opioid receptor. The resulting increase in basal Na+ permeability causes a marked depolarization of oocytes expressing the mutant GIRK2 protein. This result was observed even when the mutant GIRK2 was coexpressed with GIRK1, a situation more analogous to that seen in vivo. Thus, the increased Na+ permeability and resulting depolarization may contribute to the pathology of cerebellar granule cells and substantia nigra dopaminergic neurons observed in the weaver mice.

Recurrent varicose veins after short saphenous vein surgery: a duplex ultrasound study

Recurrent venous reflux in the popliteal fossa of patients with recurrent varicose veins following short saphenous vein surgery was assessed in 70 limbs using a duplex scanner. Incompetence of the short saphenous vein was found to be the main source (61%) of venous reflux in the popliteal fossa (43/70). The recurrence or persistence of the short saphenous vein was subdivided into four types: an intact saphenopopliteal junction, as well as an intact short saphenous vein in 20 limbs (type I): varicosities in the popliteal fossa communicating with a short saphenous vein stump in 11 limbs (type II); a residual short saphenous vein communicating with the popliteal vein via a tortuous recurrent vein in eight limbs (type III); and a segment of residual short saphenous vein with no communication with the popliteal vein in four limbs (type IV). Incompetence of a gastrocnemius vein was involved in 24 cases (34%), an incompetent popliteal area vein in one (1.4%), popliteal vein incompetence in 15 (21%), and popliteal fossa varicosities communicating with the long saphenous system in two (3%). Of 12 limbs tested pre- and postoperatively, a high termination of the short saphenous vein was demonstrated in four of seven residual incompetent short saphenous veins. Duplex scanning is recommended to assess recurrent venous reflux in the popliteal fossa. It can be used to determine the level of an incompetent saphenopopliteal junction and the level of the termination of any other incompetent vein in the management of varicose veins recurring after a short saphenous vein operation.

Combined semiclosed iliac endarterectomy and distal arterial reconstruction for multilevel arterial disease

Semiclosed iliac endarterectomy in combination with an infrainguinal vascular reconstruction has been used over the past decade in the treatment of lower-limb ischaemia. Although the early results of this combination of operations were known, the durability of the external iliac endarterectomy had not been assessed and so an effort was made to review all surviving patients by duplex scanning. Between 1985 and 1993, 48 patients (51 limbs) underwent combined semiclosed iliac endarterectomy and infrainguinal vascular reconstruction for iliac and femoropopliteal occlusive disease. Some 49% of operations were performed for limb salvage. An iliofemoral bypass graft was required twice because of failure of the endarterectomy. A variety of distal arterial reconstructions was employed. One patient required a major amputation and there were two deaths. Mean (s.d.) ankle/brachial indices (ABI) rose from 0.54 (0.14) to 0.85 (0.25) after surgery. Some 85% of the patients who underwent operation for claudication became symptom free; 83% of patients who underwent operation for limb-threatening ischaemia became symptom free or improved to mild claudication during an average of 29 months follow-up. During the follow-up period five patients underwent a further procedure because of restenoses of the external iliac artery. A duplex scanning study was performed in 22 of the 51 limbs an average of 36 months after surgery. External iliac artery stenotic lesions were found in the area of the endarterectomy in three patients. Endarterectomy of the external iliac artery from the groin is an alternative for some patients with iliac arterial disease. In a patient scheduled for an infrainguinal bypass, when an unexpectedly greater degree of athermoma is found at operation in the common femoral and external iliac arteries, this operation may be performed. The durability of the operation as assessed by follow-up duplex scan is quite acceptable.

Expression of the neuropeptide Y Y1 receptor mRNA in the human brain: an in situ hybridization study

Using cRNA in situ hybridization, the regional distribution of mRNA encoding the human Y1 receptor was investigated in the normal human brain and compared with the autoradiographic distribution of putative Y1/[125I][Leu31,Pro34]PYY binding sites. Surprisingly, relatively high levels of Y1 receptor mRNA, distributed in a ty laminar fashion, were detected in the frontal and temporal cortices; laminae I, IV and VI were particularly enriched. The claustrum and nucleus of the medial geniculate body also revealed high levels of Y1 receptor mRNA signals. Moderate levels of specific hybridization were detected in the caudate nucleus, putamen, nucleus accumbens, amygdaloid nuclei, and arcuate and paraventricular nuclei of the hypothalamus. In all these regions, only very low levels of specific [125I][Leu31,Pro34]PYY binding were detected with the exception of the dentate gyrus of the hippocampal formation which expressed rather high levels of both the Y1 receptor mRNA and its translated protein. Accordingly, the human brain can express the Y1 receptor mRNA but this may not necessarily translate into a functional receptor as revealed by low specific binding levels observed in most regions.

Functional expression and signaling properties of cloned human parathyroid hormone receptor in Xenopus oocytes. Evidence for a novel signaling pathway

Expression of human parathyroid hormone receptor (hPTHR) was obtained in Xenopus oocytes. Receptor function was detected by hormone stimulation of endogenous Ca2+-activated Cl- current. This current was blocked by injected, but not by extracellular, EGTA, confirming that the hPTHR activates cytosolic Ca2+ signaling pathways. PTH responses were acutely desensitized but were regained in 6 12 h. Injection of cAMP or analogues had no effect on either responsiveness or desensitization to hPTH. The hPTH response was more sluggish than seen with serotonin 5-hydroxytryptamine (5-HT2C) receptor. In oocytes co-expressing both hPTHR and 5-HT2C receptors, homologous desensitization was seen, but cross-desensitization was not observed. Injection of inositol 1,4,5-trisphosphate (InsP3) elicited a fast inward current similar to that induced by serotonin, and complete cross-desensitization occurred between the InsP3 and 5-HT2C responses. Desensitization by hPTH did not affect responses to either InsP3 or serotonin, but cells desensitized to injected InsP3 still responded strongly to PTH. Oocytes did not respond to either cADPR or NAADP+, but NADP+ and analogues were found to be potent inhibitors of PTH signaling. We suggest that PTH cytosolic Ca2+ signaling in oocytes either involves a novel signaling system or proceeds through a Ca2+ compartment whose responsiveness is regulated in a novel way.

Outcome of patients with symptomless carotid bruits: a prospective study

Knowledge of the natural history of symptomless carotid artery disease is important in determining the best preventative treatment for symptom-free patients. To document the progression of carotid artery disease and the clinical course of a symptomless population, 336 patients with symptom-free carotid bruits were prospectively followed up initially with oculoplethysmography and subsequently with duplex scanning. During a mean follow-up of 4.87 years, eight patients (2.4%) suffered a stroke. Thirty-seven (11.0%) experienced transient ischaemic attacks (TIAS). The cumulative event rate (TIA plus stroke) was 13.4% (45/336). The annual event rates were 0.48% for stroke, 2.26% for TIA and 2.75% for all ischaemic events. In a subgroup of 69 high-grade carotid stenoses (80-99%), 31 carotid endarterectomies were performed before the development of a TIA or stroke and 21 after the development of symptoms, while 17 lesions were followed-up non-operatively. The total event rate (TIA and stroke) was significantly greater in the non-operated compared with the operated arteries (51.0% versus 6.4% at 5 years, P=0.0034). However, most of the events which occurred in the non-operated group were TIAs (85.7%) rather than stroke. There was no difference In the death rate of the two groups (P>0.05). Review of serial duplex studies performed on 540 carotid arteries revealed that 382 arteries (70.7%) remained unchanged and 158 (29.3%) showed disease progression. Forty-four of the 540 arteries became symptomatic (TIA or stroke). In 29 of the 44, the event occurred without any change in diameter of the artery, while in 15 there was a change of at least one category greater stenosis. In 39 patients, the stenosis was at least 40% and in five the stenosis was under 40%. Nine events occurred in the patients with severe contralateral carotid stenoses (>60%). The incidence of TIA (32.2%), stroke (6.8%) and death (18.6%) was higher in patients with internal carotid artery stenoses in excess of 80% than in those with lesions between 0 and 79% stenosis (P<0.0001, P= 0.0367 and P=0.0236, respectively). In this study the incidence of cerebrovascular events was higher in patients with high-grade internal carotid artery disease, and the preservation of neurological status in patients with symptomless high-grade carotid artery stenosis was improved by carotid endarterectomy, although the overall mortality remained unchanged.

Expression of multidrug resistance-associated protein (MRP) mRNA in blast cells from acute myeloid leukemia (AML) patients

A specific and quantitative reverse-transcription polymerase chain reaction (RT-PCR) assay was developed for measuring the mRNA of the multidrug resistance-associated protein (MRP). A region corresponding to bp 3897-4471 of MRP cDNA is amplified, which encompasses approximately half of the second nucleotide-binding domain (NBD2). In two multidrug resistant (MDR) sublines of the HL-60 human acute myeloid leukemia (AML) cell line which overexpress MRP but not P-glycoprotein, the assay detects elevated levels of MRP mRNA (4- to 8-fold) relative to the drug-sensitive parental cells (designated HL-60/W). Blast cells from 24 patients with AML were also studied for MRP expression using this RT-PCR method. Expression of MRP was normalized for that of beta-actin in the blast cells, which was also determined by RT-PCR. All of these blast cell samples had MRP expression that was detectable after 35 PCR cycles. Eighteen of these patients samples had levels of expression of MRP mRNA equal to or less than that expressed by HL-60/W cells. In six patient blast cell specimens, the expression of MRP mRNA was up to 1.7-fold higher than that of HL-60/W cells. In 21 specimens, the steady-state intracellular accumulation of daunorubicin (1 microgram/ml, 3h) was also determined. The blast cells with MRP mRNA expression higher than HL-60/W had a lower median accumulation of daunorubicin compared to those whose MRP expression was less than HL-60/W, suggesting a functional defect in drug transport in the cells with higher MRP expression; a similar trend toward lower daunorubicin accumulation was also noted in the one-third of samples that displayed the highest expression of MDR1 mRNA (also determined by RT-PCR). These studies illustrate the range of expression of MRP in AML blast cell specimens. The identification of MRP overexpression in MDR AML cell lines and in some AML patient blast cells with low intracellular daunorubicin accumulation warrants further study of MRP as a component of clinical drug resistance in AML.

Expression of the neuropeptide Y Y1 receptor in human embryonic kidney 293 cells: ligand binding characteristics, in situ hybridization and receptor autoradiography

The human neuropeptide Y Y1 receptor cDNA was transfected into human embryonic kidney 293 (HEK 293) cells and used to determine the selectivity of newly developed Y1 and Y2 radioligands in a model which expresses a single NPY receptor subtype. The Y1 receptor probe, [125I][Leu31,Pro34]PYY, binds with high afinity (KD of 0.4-0.6 nM) to Y1-transfected HEK 293 cells whereas the Y2 radioligand, [125I]PPY3-36 failed to demonstrate any significant labelling. Only non-selective (PYY) or selective Y1 receptor agonists behaved as potent competitors for [125I][Leu31,Pro34]PYY binding in transfected cells. Additionally, the efficacy of the transfection method used was evaluated at both the transcriptional and translational levels. In situ hybridization revealed the heterogeneous distribution of the NPY Y1 receptor mRNA expressed in transfected HEK 293 cells. Similarly, the levels of NPY Y1 binding sites per transfected cell varied as shown using [125I][Leu31,Pro34]PYY receptor autoradiography. Taken together, these results demonstrate that HEK 293 cells transfected with the NPY Y1 receptor cDNA expressed both the related receptor mRNA and protein albeit at different levels depending upon each transfected cell. Additionally, these data further establish the selectivity of the newly developed Y1 and Y2 radioligands.

Susceptibility of idarubicin, daunorubicin, and their C-13 alcohol metabolites to transport-mediated multidrug resistance

The intracellular pharmacokinetics and cytotoxicity of idarubicin (IDA), daunorubicin (DNR), and their corresponding C-13 alcohol metabolites, idarubicinol (IDAol) and daunorubicinol (DNRol), were studied in drug-sensitive HL-60/W human leukemia cells, and in two multidrug-resistant (MDR) sublines, HL-60/Vinc (overexpress P-glycoprotein, Pgp) and HL-60/Adr (overexpress multidrug resistance-associated protein, MRP). Intracellular drug accumulation (1 micrograms/mL) and retention were measured by flow cytometry. Mean intracellular steady-state concentration (Css, fluorescence units/cell) and area under the intracellular drug concentration x time curve (AUC, Fl.U/cell.min) were calculated. Relative to the values for the respective drugs in HL-60/W cells, the Css and AUC of IDA were much higher than those of DNR in the MDR cell lines, with Css and AUC of IDAol intermediate between IDA and DNR. In the MDR cell lines, the MDR modulator cyclosporine A (CsA), in concentrations of 0.3 to 30 mumol/L, caused minimal effects on 3-hr IDA accumulation, intermediate enhancement of IDAol accumulation, and greatest enhancement of DNR accumulation. The MDR cell lines were much less resistant to IDA (3- to 16-fold) than to DNR (65- to 117-fold). This difference was not the result of IDA being more potent than DNR, since the sensitivity of HL-60/W cells to IDA differed from their sensitivity to DNR by < 2-fold. The cellular pharmacokinetics and cytotoxicity of IDA in MDR human breast carcinoma cells MCF-7/AdrVp, which overexpress the putative MDR transporter P-95, were far superior to those of DNR, and were comparable to these parameters for IDA in parental MCF-7/W cells. These studies demonstrate that the cellular pharmacology and cytotoxicity of IDA in MDR cell lines that overexpress MRP, Pgp, or P-95 are more advantageous than those of DNR, suggesting that IDA is less susceptible to the transport-mediated MDR mechanism manifested. IDA is not completely invulnerable to MDR, however, since the MDR sublines studied did display a demonstrable level of resistance to IDA, compared with their drug-sensitive counterparts. IDAol, the major plasma metabolite of IDA, demonstrated behavior intermediate between the MDR-susceptible drug DNR and its parent compound, suggesting that its cytotoxic action is subject to transport-mediated cellular defenses.(ABSTRACT TRUNCATED AT 400 WORDS)

Duplex ultrasound assessment of the venous status of the swollen leg

Between January 1991 and December 1993, duplex ultrasound characterization of venous disease in leg swelling was studied in 214 patients (261 limbs; 167 unilateral and 47 bilateral). All patients were examined with a duplex scanner, the superficial and deep venous systems were evaluated for the presence of thrombus and valvular incompetence. Of the 261 limbs, 29 (11.1%) had deep venous thrombosis, 14 (5.4%) had superficial venous thrombosis, 66 (25.3%) had deep venous incompetence (31/66 limbs also had superficial venous incompetence), 65 (24.9%) had incompetence in the superficial veins only, and five (1.9%) had deep venous obstruction resulting from a popliteal cyst or a popliteal vein ligation. Eighty-two limbs (31.4%) had no evidence of venous obstruction or incompetence at the areas evaluated. This study showed that venous obstruction and valvular incompetence had occurred in two-thirds of swollen legs examined. Some of the venous obstructions resulted from surgically treatable diseases such as a popliteal cyst, and some of the venous disorders involved the superficial venous system only. Complete venous evaluation with duplex imaging can be very helpful in the determination of the underlying cause of the swelling.

Recurrent varicose veins following high ligation of long saphenous vein: a duplex ultrasound study

Duplex scanning was used to study recurrent varicose veins in 244 limbs with previous high ligation of the long saphenous vein. The recurrent varicose veins were classified into two types according to the presence or absence of a residual long saphenous vein. Varicose veins with a residual long saphenous vein (type I) occurred in 168 limbs (68.9%). A residual long saphenous vein with an incompetent saphenofemoral junction was present in 125 limbs and one without any residual saphenofemoral junction in 43 limbs. Besides the presence of an incompetent long saphenous vein in this group, an incompetent short saphenous vein was detected in 26 limbs, incompetent perforating vein(s) in 45 limbs and incompetent deep veins in 26 limbs. Varicose veins without a residual long saphenous vein (type II) occurred in 76 limbs (31.1%). An incompetent short saphenous vein was demonstrated in 44 limbs, incompetent perforating vein(s) in 18 limbs and incompetent deep veins in 32 limbs. Of the total 244 limbs with recurrent varicose veins, long saphenous vein incompetence was involved in 168 (68.9%), short saphenous vein incompetence in 70 (28.7%), perforating vein incompetence in 63 (25.8%) and deep venous incompetence in 58 (23.8%). Although saphenofemoral junction incompetence was found to be the main source of recurrence, a segment of incompetent residual long saphenous vein, an incompetent short saphenous vein, perforating vein and deep venous system incompetence are other common sources of recurrence. A precise assessment to identify underlying venous incompetence is important for the management of recurrent varicose veins.

An etoposide-resistant lung cancer subline overexpresses the multidrug resistance-associated protein

We have characterised an etoposide-resistant subline of the small-cell lung cancer cell line, UMCC-1, derived at our centre. Subline UMCC-1/VP was developed by culturing the parent line in increasing concentrations of etoposide over 16 months. UMCC-1/VP is 20-fold resistant to etoposide by MTT assays, relative to the parent line, and is cross-resistant to doxorubicin, vincristine and actinomycin D, but not to taxol, cisplatin, melphalan, thiotepa or idarubicin. Topoisomerase II immunoblotting demonstrates a 50% reduction of the protein in the resistant subline. The UMCC-1/VP subline demonstrates a marked decrease in the accumulation of [3H]etoposide relative to the parent line, as well as a modest reduction in the accumulation of daunorubicin. Reverse transcription-polymerase chain reaction assays demonstrate no detectable mdr1 expression but marked expression of the multidrug resistance-associated protein (MRP) gene in the resistant subline. Northern blotting with an MRP cDNA probe confirms marked overexpression of the MRP gene only in the UMCC-1/VP subline. Western blotting with antisera against MRP peptide confirms a 195 kDa protein band in the UMCC-1/VP subline. Southern blotting experiments demonstrate a 10-fold amplification of the MRP gene in the resistant subline. Depletion of glutathione with buthionine sulphoximine sensitised UMCC-1/VP cells to daunorubicin and etoposide. Our studies indicate that MRP gene expression may be induced by etoposide and may lead to reduced accumulation of the drug.

Transforming growth factor alpha gene expression in cultured human keratinocytes is unaffected by cellular aging

BACKGROUND

Cultured human keratinocyte grafts have been shown to stimulate endogenous reepithelialization of both chronic nonhealing and acute partial-thickness wounds. This effect is most likely mediated by cytokines that stimulate keratinocyte growth, such as transforming growth factor alpha. The effect of cellular age on cytokine expression by cultured grafts used for this purpose is presently undefined. In this study, transforming growth factor alpha gene expression in cultured foreskin keratinocytes from donors varying in age from 2 to 82 years was analyzed semiquantitatively by two separate methods, ie, Northern hybridization and competitive polymerase chain reaction.

RESULTS

No pattern of decline in transforming growth factor alpha messenger RNA expression with increasing cellular age was observed by either analysis.

CONCLUSION

The results indicate that expression of transforming growth factor alpha by cultured grafts may not be significantly affected by increasing cellular age and suggest that, even in the elderly, cultured autografts may be effective as pharmacologic agents for wound treatment.

Normal mouse skin lymphocyte, Langerhans cell, and keratinocyte responses to intradermal injections of interferon-alpha and interferon-gamma

To investigate the skin immune responses induced by intradermal injections of interferon-alpha (IFN-alpha) and interferon-gamma (IFN-gamma), normal C3H mice were injected intradermally with murine recombinant interferon-alpha (rIFN-alpha), interferon-gamma (rIFN-gamma), or the combination of rIFN-alpha and rIFN-gamma, three times per week for 2 or 4 weeks. Contralateral sites were similarly injected with placebo (saline). The results showed that after 6 or 12 injections of rIFN-alpha (10,000 IU/per injection), epidermal ATPase+ and Ia+ Langerhans cells (LGs) decreased significantly (p < 0.01 and p < 0.05) but dermal lymphocytic infiltrates, including CD3+ (pan-T cells), L3T4+ (T helper cells), Lyt-2+ (T suppressor/cytotoxic cells), MOMA+ (macrophages and monocytes), and dermal Ia+ cells, increased significantly (p < 0.01) compared with both saline injection sites and untreated skin. In contrast to rIFN-alpha, 6 injections of 10,000 IU rIFN-gamma failed to induce significant changes in either epidermal LGs or dermal lymphocytic infiltrates, except for an increase in dermal MOMA+ cells. High-dose rIFN-gamma injections (50,000 IU) strongly enhanced the expression of Ia antigen in epidermal keratinocytes (KCs), increased dermal lymphocytic infiltrates, and decreased the LGs in a similar pattern to that of rIFN-alpha. Furthermore, rIFN-gamma (50,000 IU) injections induced Ia antigen expression on the KCs in the contralateral saline injection areas, suggesting a systemic effect. Injections of a combination of rIFN-alpha and rIFN-gamma failed to show synergism for induction of skin immune responses.

Identification of a novel protein tyrosine phosphatase with sequence homology to the cytoskeletal proteins of the band 4.1 family

Use of the polymerase chain reaction (PCR) in conjunction with Southern hybridization, using probes corresponding to known phosphatase sequences, resulted in the identification of rat cDNA clones encoding a novel protein tyrosine phosphatase which was termed rPTP2E. The cDNAs comprise 5,543 bp and predict a polypeptide of 1175 amino acids possessing a single catalytic domain at its C-terminus. The N-terminal region of the deduced polypeptide displays high sequence homology to the cytoskeleton-associated proteins of the band 4.1 family. A variant form, termed rPTP2E1, was also identified which contains the catalytic domain only. rPTP2E and rPTP2E1 were expressed in various rat tissues, particularly abundantly in adrenal glands. The catalytic domain of PTP2E was expressed in Escherichia coli and was shown to possess specific protein tyrosine phosphatase activity. The identification of rPTP2E suggests the existence of a subfamily of band 4.1 domain-containing PTPs which may play an important role in signalling pathway and control of cytoskeletal integrity.

Computerized quantitation of synergism and antagonism of taxol, topotecan, and cisplatin against human teratocarcinoma cell growth: a rational approach to clinical protocol design

BACKGROUND

Cisplatin-based induction chemotherapy may achieve a complete response (i.e., no sign of tumor following treatment) in 70%-80% of patients with germ cell tumors. However, only a minority of patients in whom the firstline regimens fail are cured with the salvage regimens.

PURPOSE

The aim of these studies was to identify new agents or new regimens for the treatment of germ cell tumors by carrying out quantitative assessment in vitro of two promising new antitumor agents (paclitaxel [Taxol] and topotecan) and three more established agents (cisplatin, vincristine, and etoposide). These agents were used singly or in two- and three-drug combinations and were selected because they represent five distinct categories of antineoplastic mechanisms.

METHODS

The combination index-isobologram method, which is based on the median-effect principle developed by Chou and Talalay, was used for computerized data analysis. This method was selected because it takes into account both the potencies of each drug and combinations of these drugs and the shapes of their dose-effect curves.

RESULTS

Synergism against the growth of teratocarcinoma cells resistant to cisplatin (833K/64CP10 cells) was greater than against the growth of parent 833K cells. The degrees of synergism were in the following order: cisplatin + topotecan > or = paclitaxel + cisplatin + topotecan > paclitaxel + topotecan > or = paclitaxel + etoposide > paclitaxel + cisplatin + etoposide > paclitaxel + cisplatin. All other combinations showed nearly additive effects or moderate antagonism. The degrees of antagonism were as follows: cisplatin + etoposide > or = paclitaxel + vincristine > paclitaxel + cisplatin + vincristine > cisplastin + vincristine. The combination of paclitaxel and cisplatin was synergistic against 833K/64CP10 cells and moderately antagonistic against 833K cells. Since the combination of paclitaxel, cisplatin, and topotecan and the two-component combinations of these drugs (cisplatin + topotecan and paclitaxel + topotecan) showed synergism stronger than that of other combinations, these three drugs were selected for illustrating detailed data analysis, using a computer software program developed in this institute.

CONCLUSIONS AND IMPLICATIONS

Our findings suggest that, as a result of synergy, the doses of these agents needed to achieve an antitumor effect may be reduced by twofold to eightfold when these agents are given in combination. The present quantitative data analyses for synergism or antagonism provide a basis for a rational design of clinical protocols for combination chemotherapy in patients with advanced germ cell tumors.

Localization of diazepam-binding inhibitor and peripheral type benzodiazepine binding sites in the rat ovary

Diazepam-binding inhibitor (DBI) is the precursor of a family of peptides, including an octadecaneuropeptide (ODN), that share with DBI the ability to specifically displace benzodiazepines (BZD) from their receptors. An association of ODN with the peripheral type BZD receptors (PBR) has been reported in the brain and a few peripheral tissues. In order to investigate whether DBI and PBR are present in ovarian tissue, we have localized DBI by means of immunocytochemistry, in situ hybridization and autoradiography of PBR in the rat ovary. Immunocytochemical localization was achieved by means of rabbit antibodies developed against rat ODN. Immunostaining was located in the cytoplasm of the theca interna, corpus luteum and interstitial gland cells, but not in the granulosa cells. Hybridization signal obtained following in situ hybridization with a [35S]-labelled single-stranded RNA probe complementary to DBI mRNA was observed in all the steroid-secreting cells, including granulosa cells of developing and mature follicles. Autoradiographic localization of PBR obtained by incubating ovary sections with [3H] PK11195, a ligand selective for PBR, revealed the presence of specific labelling in all the steroid-secreting cells. These results, which demonstrate for the first time that the ovarian steroid-secreting cells contain both PBR and its endogenous ligand, suggest that the BZD receptor might be involved in the regulation of ovarian function.

The value of duplex scanning in surveillance of infra-inguinal vein and synthetic grafts

The contribution of duplex scanning to improving early diagnosis of graft stenosis was evaluated in 195 patients after infrainguinal bypass procedures. Over a 31 month period. 406 duplex scans were obtained on 232 limbs with 191 vein and 41 polytetrafluoroethylene (PTFE) grafts. Peak systolic velocities > 200 cm/s with spectral broadening and lumen reduction on B-mode image were the criteria adopted for identification of a haemodynamically significant (> 50%) stenosis. Sixty-one stenoses were identified in 55 of the grafted limbs. Thirty-three of the 55 limbs had a subsequent angiogram. The angiogram showed graft occlusion in six limbs, graft stenosis in 18, and native artery stenosis in four. Twenty-one of the grafts had the angiogram within 1 month after the duplex had detected graft stenosis, and one (4.76%) became occluded in this interval. Seven had an angiogram more than 1 month after the duplex study, and five (71.4%) had become occluded. The angiographic study did not confirm a graft stenosis in five limbs. Three were submitted to operation and stenosis was confirmed. Seventeen graft thromboses were detected by duplex scanning. Graft thrombosis was demonstrated following a previous negative duplex scan in one of the 106 vein grafts (0.94%), and in four of 30 PTFE grafts (13.3%). Duplex scanning is effective in the detection of graft stenosis. The precise anatomical location is less accurate when in the region of an anastomosis. Early attention should be taken when duplex studies suggest critical stenosis because there is a high risk of occlusion. Polytetrafluoroethylene grafts tend to thrombose without a precursory focal stenosis.

An anatomic source of false venous reflux with continuous wave Doppler

BACKGROUND

The limitations of continuous wave (CW) Doppler have been recognized in the assessment of venous reflux since CW Doppler is not able to distinguish reflux signals from more than one vein. In our experience, some regions with venous reflux suggested by CW Doppler were noted to have no reflux in any individual vein during duplex studies.

OBJECTIVE

The aim of the study was to assess the anatomic source of the venous reflux suggested by CW Doppler but not confirmed by duplex ultrasound.

METHODS

Five hundred and fifty-one consecutive lower limbs with primary or recurrent varicose veins were examined with CW Doppler and subsequently by color-coded duplex ultrasound to assess the source of venous reflux.

RESULTS

The duplex ultrasound study revealed no reflux in 44 specific regions (8%) where reflux had been indicated by CW Doppler. Two types of anatomy were noted. Two or more superficial veins joined the deep venous system via a common junction in 25 cases. A descending vein joined the deep venous system in 19 cases.

CONCLUSION

A bidirectional Doppler signal in a region of venous junction without any incompetent veins can be misinterpreted as venous reflux. A careful examination of veins not only at the region of the junction, but also at some distance down the stem of the vein is important during CW Doppler or duplex assessment.