[Surgery for acute arterial emboli to the arm]

During a 5-year period (1987-1992) we removed under local anesthesia 20 emboli and 2 thrombi from the arms of 18 patients aged 60-90 using a Fogarty catheter. 18 of the emboli (90%) were of cardiac origin. 1 patient had thrombosis of the axillary artery (2 episodes). The occlusions were brachial in 14 (70%), axillary in 5 (25%), and radial in 1. From 1.5 hours to 1 week elapsed between onset of symptoms and operation. 9 patients underwent arteriography. Surgery was successful in 19 (95%). Limb necrosis developed in a patient operated on 1 week after onset of symptoms. Necrosis progressed despite a palpable radial pulse. 33 patients (15%) died of causes unrelated to the operation: 2 had terminal cardiac disease and the third concomitant occlusion of the superior mesenteric artery. Early surgical exploration is advocated for acute arterial embolism of the upper extremity. Ischemic changes may be reversible even later than 24 hours from onset of symptoms. Routine arteriography is not needed before surgical exploration of these cases.

Effect of neuromuscular blockade on facial nerve monitoring

Direct facial nerve stimulation and monitoring during cerebellopontine angle (CPA) tumor surgery are critical for identification and preservation of function. Electrically evoked facial nerve monitoring was compared with ulnar train-of-four monitoring under progressive neuromuscular blockade. Using a rabbit model, the facial nerve function of six controls was compared to that of six specimens with acute or chronic injuries. Eight of 18 patients who had undergone CPA tumor resection during one year were also studied. Regression analysis correlated between ulnar nerve monitoring and facial electromyographic (EMG) peak voltage in all groups. Facial EMG was measurable, even with 75 percent receptor blockade. The results of this study support the hypothesis that high degrees of neuromuscular blockade do not preclude satisfactory EMG monitoring of the facial nerve during CPA tumor surgery. This study did demonstrate that chronically injured facial nerves may show greater sensitivity to the effects of neuromuscular blockade. Lower levels or avoidance of neuromuscular blockade should be employed under these circumstances.

Interleukin-2 transcription is regulated in vivo at the level of coordinated binding of both constitutive and regulated factors

Interleukin-2 (IL-2) transcription is developmentally restricted to T cells and physiologically dependent on specific stimuli such as antigen recognition. Prior studies have shown that this stringent two-tiered regulation is mediated through a transcriptional promoter/enhancer DNA segment which is composed of diverse recognition elements. Factors binding to some of these elements are present constitutively in many cell types, while others are signal dependent, T cell specific, or both. This raises several questions about the molecular mechanism by which IL-2 expression is regulated. Is the developmental commitment of T cells reflected molecularly by stable interaction between available factors and the IL-2 enhancer prior to signal-dependent induction? At which level, factor binding to DNA or factor activity once bound, are individual regulatory elements within the native enhancer regulated? By what mechanism is developmental and physiological specificity enforced, given the participation of many relatively nonspecific elements? To answer these questions, we have used in vivo footprinting to determine and compare patterns of protein-DNA interactions at the native IL-2 locus in cell environments, including EL4 T-lymphoma cells and 32D clone 5 premast cells, which express differing subsets of IL-2 DNA-binding factors. We also used the immunosuppressant cyclosporin A as a pharmacological agent to further dissect the roles played by cyclosporin A-sensitive factors in the assembly and maintenance of protein-DNA complexes. Occupancy of all site types was observed exclusively in T cells and then only upon excitation of signal transduction pathways. This was true even though partially overlapping subsets of IL-2-binding activities were shown to be present in 32D clone 5 premast cells. This observation was especially striking in 32D cells because, upon signal stimulation, they mobilized a substantial set of IL-2 DNA-binding activities, as measured by in vitro assays using nuclear extracts. We conclude that binding activities of all classes fail to stably occupy their cognate sites in IL-2, except following activation of T cells, and that specificity of IL-2 transcription is enforced at the level of chromosomal occupancy, which appears to be an all-or-nothing phenomenon.

Prevention of thromboembolism in spinal cord injury: role of low molecular weight heparin

Deep vein thrombosis (DVT) and pulmonary embolism (PE) are major causes of morbidity and mortality in patients with acute spinal cord injury. Our preliminary studies indicated that low molecular weight heparin (LMWH) was significantly more effective than standard heparin in preventing these complications. We have now extended these studies by screening an additional 122 patients and treating 60 who met predefined criteria with LMWH in a dose of 3,500 anti-Xa U given subcutaneously once daily for 8 weeks. All patients were examined daily at bedside and had regularly scheduled venous ultrasonography; those with abnormalities had confirmatory venography and lung scans. Postmortem examinations were conducted in those who died. Forty completed the trial without incident, 6 had DVT (4 proximal and 2 distal), 1 had a fatal PE, 1 had postoperative bleeding requiring discontinuation of the LMWH, 10 were transferred or discharged, and 2 died of respiratory failure. The percentage of patients free of thrombosis or bleeding after 8 weeks of treatment was 85.9 +/- 5.0% standard error of mean (SEM). Thirty-three patients entered a follow-up observation period of 4 weeks without thromboprophylaxis; 2 weeks into this period 1 had a proximal DVT and 1 had a fatal PE; the course of the remainder was uneventful. We conclude that LMWH compares favorably with standard heparin in preventing venous thromboembolism, and is associated with significantly less bleeding. Eight weeks of prophylaxis seems adequate for most patients.

A transcriptional regulatory element common to a large family of hepatic cytochrome P450 genes is a functional binding site of the orphan receptor HNF-4

Hepatic cytochrome P450 (CYP) genes, including members of CYP1 to CYP4 families, comprise the majority of the CYP gene superfamily. Previous study has demonstrated that HepG2-specific transcriptional activation of two CYP2C genes was dependent on a common element that bound a HepG2 nuclear protein designated HPF-1 (Venepally, P., Chen, D., and Kemper, B. (1992) J. Biol. Chem. 267, 17333-17338). This cis-acting element is highly homologous to the hepatocyte nuclear factor 4 (HNF-4) binding motif and is present in the promoters of more than 20 other CYP2 genes. To investigate the relationship between HPF-1 and HNF-4, we have compared their tissue distribution, DNA binding, and immunochemical characteristics, as well as transcriptional activity of their recognition elements. DNase I footprint analyses and gel-shift assays indicated that HPF-1, like HNF-4, was present in liver and kidney, but not brain and spleen. Both factors bound to either the HPF-1 site in the CYP2C2 promoter or an HNF-4 site in the human apolipoprotein CIII promoter. These complexes could be "supershifted" by an antiserum specific for HNF-4. When the sequence of the HPF-1 site in the CYP2C2 promoter was changed to that of the apolipoprotein CIII HNF-4 site, comparable transcriptional activities were obtained with the wild-type promoter and the HNF-4 mutant in transfected HepG2 cells. Cotransfection of HNF-4 with CYP2C2 promoter-luciferase constructs in COS-1 cells indicated that HNF-4 could trans-activate the promoters containing the HPF-1 site. These results indicate that the HPF-1 motif is a functional HNF-4-binding site, and the common immunological properties indicate that HPF-1 and HNF-4 are closely related and possibly identical. HNF-4, therefore, may act as a common regulator for the liver-specific expression of many CYP2 genes.

[The prognostic characteristics of hypertensive left ventricular hypertrophy in a rural population]

One hundred and twenty-six rural hypertensive patients with ECG left ventricular hypertrophy (HT-LVH) were followed up for 10 years to investigate the prognostic characteristics in a population with low prevalence of hypertension (2.93%) and low plasma cholesterol (4.59 +/- 1.00mmol/L). A cohort of age, sex, region and occupation matched hypertensives without LVH (HT, n = 163) and normotensives (NT, n = 275) served as controls. The major cause of death in rural hypertensives with ECG LVH in this study was stroke (56.8%). After stratification of BP, no significant difference of stroke risk was found between patients with LVH and hypertensives without LVH, while cardiovascular risk in the patients with LVH plus ST segment depression persisted. LVH per se seems not to be an independent factor for stroke. The high stroke rate in patients with LVH may be ascribed to the coexisting higher level of BP. After adjustment of coexisting hypertension, ECG LVH based on voltage only was not an independent risk factor of stroke and cardiovascular events, while LVH plus ST segment depression was closely related to cardiovascular events. In this low level, plasma cholesterol did not affect the mortality rate of stroke.

Pituitary adenylate cyclase-activating peptide in the adrenal gland of mammals: distribution, characterization and responses to drugs

The occurrence, cellular distribution and nature of the 27-amino acid form of pituitary adenylate cyclase-activating peptide (PACAP-27) in the adrenal glands of mammals was investigated by means of immunohistochemistry, radioimmunoassay and chromatography. The concentrations (pmol/g wet weight) of PACAP-27-like immunoreactivity (LI) varied considerably between the species examined: mouse (n = 8), 12.1 +/- 2.0; hamster (n = 4), 9.1 +/- 1.5; rat (n = 13), 2.0 +/- 0.3; cow (n = 3), 0.8 +/- 0.1, and pig (n = 5), 0.7 +/- 0.1. Upon HPLC, the immunoreactivity in extracts of rat, mouse and hamster adrenals coeluted with synthetic PACAP-27 while the immunoreactivity in extracts of cow and pig adrenals eluted as less hydrophobic material. Immunohistochemistry revealed the presence of PACAP-27-LI in the noradrenaline-storing chromaffin cells of the adrenal medulla. No nerve fibers exhibiting PACAP-27-LI could be detected. The effects of drug administration in vivo on the stores of PACAP-27-LI in the rat adrenal were studied and compared with the effects on the adrenal stores of neuropeptide Y (NPY)-LI. Splanchnic activation following insulin-induced hypoglycemia elicited a 41% depletion of NPY-LI 2 h after insulin injection, while the concentrations of PACAP-27-LI remained unchanged. Two days after reserpine administration the stores of PACAP-27-LI and NPY-LI were depleted by 62 and 41%, respectively. Two days later, the concentrations of NPY-LI were increased to 216% of controls, while the concentrations of PACAP-27-LI were similar to that of controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Transfected MCF-7 cells as a model for breast-cancer progression

The MCF-7 human breast carcinoma cell line has been used as a recipient for eukaryotic plasmid expression vectors to determine the effects of growth factor and growth factor receptor overexpression on the estrogen-dependent, antiestrogen sensitive and poorly metastatic phenotypes exhibited by this line. Overexpression of some members of the erbB family of ligands and receptors were found to have some effects on these phenotypes. However, only when two members of the fibroblast growth factor family, FGF-1 and FGF-4, were overexpressed was progressive in vivo growth observed is either ovariectomized nude mice without estrogen supplementation or in mice that received tamoxifen treatment. FGF transfected cells also exhibited an increased ability to form micrometastases. The implications of these results with regard to the possible role of the paracrine and autocrine effects of angiogenic growth factor production in breast cancer progression are discussed.

The biology and physiology of the ECL cell

The enterochromaffin-like (ECL) cells, which are the predominant endocrine cell type in the acid-producing part of the vertebrate stomach, are characterized by numerous, electron-lucent vesicles and few electron-dense granules in the cytoplasm. The biological and physiological significance of the ECL cells remains poorly understood. They produce and store histamine and pancreastatin and are thought to produce an as yet unidentified peptide hormone. The most important clue to their function is their willingness to respond to changes in circulating gastrin. The present review presents current knowledge of the biology and physiology of the rat stomach ECL cells. Examination of serially sectioned ECL cells has revealed that the cytoplasmic vesicles almost invariably contain an electron-dense core, suggesting that perhaps the distinction between granules and vesicles is artificial. We propose a life cycle of the secretory organelles in the ECL cells with a progressive development from granules to vesicles. The results showed that the gastrin-evoked release of histamine and pancreastatin was accompanied by loss of vesicles, and that synthesis of histamine and pancreastatin was accelerated by sustained infusion of gastrin, a treatment that was associated with renewal of vesicles. The events described are instrumental in bringing about a change in the "steady state" or "equilibrium" of the ECL cells, from a non-stimulated, resting state to a gastrin-stimulated, active state. This change is attained within six to eight hr. The next "steady state" change is that from "normal-sized" but active ECL cells to "hypertrophic" ECL cells. The increase in cell size is complete after about one week. The gastrin-evoked increase in the ECL cell self-replication rate is maximal after about 10 days, after which time there is a gradual return back to pre-stimulation values. The ECL cell density increases fairly slowly and does not reach maximum (four-fold increase) until after 20 weeks hypergastrinemia. The activity of the histamine-forming enzyme, histidine decarboxylase, is elevated by gastrin and remains elevated for as long as the gastrin stimulus is maintained (the longest time studied was 20 weeks). The physiological significance of the ECL cells is probably related to their capacity to produce and store histamine and an as yet unidentified peptide hormone. The ECL cells are thought to be the source of histamine necessary for the gastrin-evoked acid response. In addition, preliminary evidence suggests that the ECL cells and the anticipated ECL cell hormone play a role in bone formation.

Early onset posttraumatic cystic myelopathy complicating spinal cord injury

Three cases of posttraumatic cystic myelopathy occurring early in the postinjury period are reported. A patient with C5 tetraplegia developed bilateral upper extremity paresthesias and right upper extremity weakness 2 and a half months postinjury necessitating immediate syringo-subdural shunting. A patient with C6 tetraplegia complained of left upper extremity paresthesias 2 months postinjury. A syringoperitoneal shunt was placed 19 months postinjury due to new onset intermittent weakness of the right upper extremity. A patient with C4 tetraplegia developed right upper extremity paresthesias, sensory loss, and weakness 56 days postinjury; it was treated conservatively. Two years postinjury he required surgery because of progression of symptoms. A review of the literature reveals that posttraumatic cystic myelopathy has been found to be an incidental pathologic finding at autopsy within 2 months postinjury. However, sensory and motor loss have not been clinically described as an early complication of spinal cord injury. We conclude that posttraumatic cystic myelopathy should be considered in the differential diagnosis of motor or sensory loss occurring early in the postinjury period.

Pharmacokinetics, acid-base balance and intraocular pressure effects of ethyloxaloylazolamide--a novel topically active carbonic anhydrase inhibitor

Studies evaluated a novel series of biscarbonylamides of 2-amino-1,3,4-thiadiazole-5-sulfonamide (2-ATS) for topical use as ocular hypotensive carbonic anhydrase inhibitors (CAI). Transcorneal accession rate constants (k(in)) for ethyloxaloylazolamide (EtOxAz), ethylsuccinylazolamide (EtSuxAz) and ethyladipoylazolamide (EtAdipAz), and activity against carbonic anhydrase (CA) were determined in vitro by an enzymatic assay and High Performance Liquid Chromatography (HPLC). The ocular hypotensive effect was measured by pneumatonometry on conscious normotensive New Zealand White (NZW) rabbits, using masked, randomly assigned paired-eye design for treatment vs. control. At various time points following treatment, aqueous humor, ciliary processes and corneal buttons were collected and assayed for drug concentrations using enzymatic assay and HPLC. Transcorneal accession rates for the novel compounds were 1.5 to 18 times that of the parent compound, acetazolamide (Actz). The activity factor for EtOxAz was 72.8 x 10(3) hr-1 of 23 times that of Actz. The activity factors for EtSuxAz and EtAdipAz were 6.8 and 1.1 x 10(3) hr-1, respectively. Subcutaneous administration of EtOxAz. EtSuxAz, and EtAdipAz, in 225 mumol kg-1 concentrations, induced a significant decrease in the intraocular pressure (IOP) at 1 hr post injection of 4, 5.8 and 6 mmHg for EtOxAz, EtSuxAz and EtAdipAz, respectively (P < 0.05 for each). Topical application of 75 mM EtOxAz lowered the IOP by 3.0 mmHg (P < 0.05). This effect was maximal after 60 min and persisted for at least 5 hr. EtSuxAz and EtAdipAz did not alter the IOP significantly when given topically. Subcutaneous administration of the three compounds was associated with acidosis (pH as low as 7.21). Topical application did not cause any changes in the acid-base balance. There was a direct correlation between the amount of drug delivered to the ciliary process and the magnitude of ocular hypotensive effect. Following topical application EtOxAz reached the ciliary epithelium in concentrations sufficient to inhibit more than 99.95% of the ciliary carbonic anhydrase (> 8 microM), while plasma drug concentrations were below the limit of detection by the assay (< 0.2 microM). Within the first hour after topical application, half of the EtOxAz was eliminated from the anterior uvea. In summary, EtOxAz is a topically effective CAI. Structural modifications of thiadiazole sulfonamides, with the increase of both water and lipid solubilities, improved the transcorneal accession while preserving sufficient CA inhibitory activity, resulting in a significant IOP decrease following topical application of EtOxAz.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effects and mechanism of total saponins of Panax Notoginseng on anti-inflammation and analgesia]

In this study the effects of total saponins of Panax notoginseng (TSPN) and electroacupuncture (EA) were compared. Liquid paraffin was intraperitoneally injected (0.1 ml/mouse) to establish the animal model with inflammation. The mice were randomly divided into 4 groups with different treatments for 7 days: EA group, TSPN group (100 mg.kg intraperitoneal administration), Naloxone (Nx) plus TSPN group and EA plus TSPN group. The pain threshold was measured by a detector (EQ-9E) and the nitroblue tetrazolium test (NBT) for polymorphonuclear neutrophil (PMN) bacteriocidal activity and the alpha-naphthyl acetate esterase (ANAE) histochemical staining for detection of the focal pattern lymphocyte subpopulation and the toluidine blue histochemical staining for detection of degranulation rate peritoneal mast cells were performed. The results showed that in TSPN, EA and EA plus TSPN group the pain threshold was elevated significantly, the enumeration of NBT positive PMN and the ANAE-F lymphocyte subpopulation was enhanced. All the above effects could be partially inhibited by naloxone. Between TSPN group and Nx group the degranulation rate of peritoneal mast cells had no significant difference. Since the TSPN and EA have similar effects e.g. anti-inflammatory, analgesic and immunomodulatory action, it suggested that the TSPN might be somewhat agonist of the opioid like peptide receptor without addiction side reactions.

Rheologic and hemodynamic characteristics of red cells of mouse, rat and human

The present study compares hematologic, rheologic and hemodynamic characteristics of red cells from mouse, rat and human. Red cells in these species are biconcave discs that show significant differences in diameter and mean corpuscular volume (MCV). However, differences in mean corpuscular hemoglobin concentration (MCHC) are not significant. Viscosity measurement of washed red cell suspensions (in each case the medium osmolarity adjusted to match plasma osmolarity) showed significant interspecies differences at shear rates of 37.5 and 750 sec-1 as follows: Human > rat > mouse. Hemodynamic and microcirculatory behavior of these red cells was investigated in the artificially perfused ex vivo mesocecum vasculature of the rat. Hemodynamic measurements in the whole ex vivo mesocecum preparation revealed maximal increase in the peripheral resistance unit (PRU) for the human red cells followed by the rat and mouse red cells, respectively at a hematocrit (Hct) of 40%. Further, measurements of red cell velocities (Vrbc) in single arterioles of the mesocecum vasculature, during sustained perfusion with washed red cell suspensions, showed that at any given perfusion pressure (Pa), Vrbc for both mouse and rat red cells was higher than that for human red cells, while Vrbc for mouse red cells was higher than that for the rat. These results demonstrate that the microvascular flow behavior of these red cells is likely to be influenced by both physical and rheologic characteristics.

ECL cells: biology and pathobiology

During recent years, the so-called ECL cells of the acid-producing part of the stomach have attracted much attention, mainly due to the fact that mice and rats were found to develop gastric carcinoids (ECL cell tumors) following life-long treatment with blockers of acid secretion. These observations touched off concern about the safety of the long-term clinical use of such drugs. The ECL cells are the predominant endocrine cell population in the oxyntic mucosa. They produce histamine, chromogranin A/pancreastatin and an as yet unidentified peptide hormone. They respond to gastrin by the release of secretory products; more long-term responses include adaptation to the gastrin stimulus, hypertrophy and hyperplasia. Intravenous infusion of maximally effective doses of gastrin promptly reduced the number of cytoplasmic vesicles in the ECL cells and their content of histamine and pancreastatin. Despite the ongoing infusion of gastrin, the number of vesicles and the content of histamine and pancreastatin were back to normal 4-6 h after the start of the infusion. The histidine decarboxylase (HDC) activity and HDC mRNA level increased progressively until plateaus were reached after 6-8 h of gastrin infusion. The size of the ECL cells started to increase about 4 days after the start of a subcutaneous gastrin infusion (resulting in half-maximally effective serum gastrin concentrations). The ECL cell size reached maximum after about 2 weeks and then remained at this level.The number of cytoplasmic vesicles was increased; this effect seemed to reach a maximum after 1-2 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Activation of the leu-500 promoter: a topological domain generated by divergent transcription in a plasmid

The Salmonella typhimurium leu-500 promoter is active only in topA strains. In an earlier study (Chen, D., Bowater, R., Dorman, C., & Lilley, D. M. J. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 8784-8788), we showed that the activity of this promoter on a circular plasmid is a function of the transcription and translation of an adjacent tetA gene, and we suggested that the effect arises because of increased local negative superhelix density due to transcription (Liu, L. F., & Wang, J. C. (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 7024-7027) initiated at the tetA promoter. In this study we show that translation of the 5' (N-terminal) section of tetA is required for activity of the leu-500 promoter, consistent with a requirement for membrane association of TetA. We have also shown the importance of a second transcription unit, the ampicillin resistance gene bla, in the activation of the leu-500 promoter. Thus the activity of the leu-500 promoter was reduced by partial deletion or premature termination of bla and was increased when the transcription of bla was boosted by the insertion of the stronger tac promoter. However, even in the latter situation the role of the tetA gene is dominant, and deletion of the tetA gene reduced activity of the leu-500 promoter to very low levels. These results suggest the existence of a topological domain defined by the divergent bla and tetA transcription units. Membrane insertion at tetA is essential to provide an anchorage point.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of traditional and reversed bandwidth knowledge of results on motor learning

The effects of two types of bandwidth (BW) knowledge of results (KR) were investigated on the acquisition and immediate retention of a timing task. Traditional and reversed BW KR groups were compared with two yoked control groups. Forty-eight randomly assigned subjects completed 60 acquisition trials and 20 no-KR retention trials. Acquisition analysis indicated a greater timing accuracy for the traditional BW group in comparison to the reversed BW group. During retention, less absolute constant error was found for both BW groups than for their yoked controls. Absolute performance changes were analyzed to further differentiate the contributions of quantitative and qualitative KR available in both types of BW conditions. This analysis revealed a significant KR x Trial Type interaction. Reliable changes in performance were observed after quantitative trials for the traditional BW group, whereas for the reversed BW group, reliable changes were observed after qualitative trials. This reversed BW group finding, along with the retention accuracy findings, indicated that the qualitative information was used to learn the timing task.

The prognostic characteristics of hypertensive left ventricular hypertrophy in a population with low prevalence of hypertension and low plasma cholesterol

One hundred and twenty-six hypertensive patients with ECG left ventricular hypertrophy (HT-LVH) were followed for 10 years to investigate the prognostic characteristics in a population with low prevalence of hypertension (2.93%) and low plasma cholesterol (4.26 +/- 0.91 mmol/L). A cohort of age-, sex-, region- and occupation-matched, randomized hypertensives without ECG-LVH (n = 163) and normotensives (n = 275) served as controls. HT-LVH was found to be associated with an increased risk of overall death, stroke mortality and cardiovascular mortality. The major cause of death in rural hypertensives with ECG-LVH was stroke (56.8%). After adjusting BP and BP stratification, no significant difference of stroke risk was found between patients with and without LVH, while cardiovascular risk persisted in patients with LVH plus ST segment depression. LVH per se did not appear to be an independent factor for stroke death. Higher stroke mortality in patients with LVH may be ascribed to the coexisting higher level of BP. Furthermore, after adjusting for the coexisting hypertension, ECG-LVH in terms of voltage only was not related to the prognosis of stroke and cardiovascular death. The mortality rate of stroke was not affected by plasma cholesterol levels, as the levels seen were in a low range.

Biodistribution of calcitonin encapsulated in liposomes in mice with particular reference to the central nervous system

The biodistribution of [125I]porcine calcitonin (pCT) encapsulated in reverse-phase evaporation vesicles (REVs) in mice upon the intravenous administration was examined. It was found that sulfatide significantly improved the stability of REVs in vivo, and altered the relative distribution of [125I]pCT encapsulated in liposomes in mice. These sulfatide-containing REVs were able to target [125I]pCT into the liver and central nervous system (CNS) reasonably well, with the maximal effect of about 40% and 2% of the injected doses occurring at 30 min and 90 min, respectively, after injection. Neither free [125I]pCT, nor sulfatide-free liposome-encapsulated [125I]pCT, nor a mixture of free [125I]pCT and empty sulfatide liposomes was effective. [125I]pCT was widely distributed in the CNS, with predominance in hypothalamus, brainstem, striatum and spinal cord. The results indicate that pCT encapsulated in sulfatide-containing liposomes is able to pass through the blood-brain barrier (BBB), and calcitonin, thus encapsulated, may be applicable to studies on its functions in the CNS.

Influence of local finger cooling on laser Doppler flux and nailfold capillary blood flow velocity in normal subjects and in patients with Raynaud's phenomenon

We examined the influence of local cooling (-15 degrees C, 60 sec) on blood flow velocity in nailfold capillaries and on laser Doppler flux (LDF) at the fingertip in 12 patients with primary Raynaud's phenomenon (PRP) and 13 patients with secondary Raynaud's (SRP) in comparison with 10 health controls. Skin temperature at the pulp of the finger decreased significantly during local cooling in RP but not in controls. LDF before cooling was comparable between patients and controls and dropped significantly under cooling. Flux motions at the fingertip were present in all individuals with 7.9-9.1 cycles/min. Flux motions persisted throughout the cooling test and faded away in 5 patients (1 PRP, 4 SRP) with cooling. Frequency of LDF motions was little influenced by a change in skin temperature. The amplitudes were dampened in relation to the drop in LDF level during local cooling in patients with RP. We conclude that LDF does respond to local cooling of the fingertip by significant decrease of perfusion but not with regard to flux motions. The wide overlap of the single values does not allow as good a separation of patients with RP from controls as capillary microscopy.

Effects of low level prenatal 60Co gamma-irradiation on postnatal growth and behavior in mice

Pregnant Kun Ming strain mice were exposed to a total dose of 0, 0.1, 0.2, or 0.4 Gy from 60Co gamma-rays from the 13th to the 18th days of gestation. An overall delay of the appearance of two physiologic markers (pinna detachment, eye opening) and the age of acquisition of four reflexes (surface righting, air righting, auditory startle, visual placing) was observed in offspring exposed to 0.2 or 0.4 Gy in utero. Postnatal growth retardation, shortened length of hanging time, inhibited exploratory activity in the hole board test (decreased number of head-dipping), and hyperactivity in the open field test (shortened latency to leave the center area and increased number of squares entered) were also found among the offspring exposed to 0.2 Gy or more in utero. The results indicate that 0.1-0.2 Gy may represent a threshold range in mice for certain physiologic and behavioral effects resulting from continuous exposure to 60Co gamma-rays on the 13th-18th days of gestation.

Hypercholecystokininemia produced by pancreaticobiliary diversion causes gastrin-like effects on enterochromaffin-like cells in the stomach of rats subjected to portacaval shunting or antrectomy

Gastrin and possibly cholecystokinin (CCK) control the activity and growth of the histamine-containing endocrine cells, the enterochromaffin-like (ECL) cells, in the oxyntic mucosa of the rat. Portacaval shunting (PCS) is known to activate the ECL cells through as yet unknown mechanisms. PCS also exaggerates the ECL cells' response to gastrin, whereas antrectomy causes hypotrophy and hypoplasia of the ECL cells. A recent study showed that the ECL cells failed to respond to sustained hyperCCKemia caused by pancreaticobiliary diversion (PBD). In the present study we investigated whether PBD-produced hyperCCKemia influenced the effects of PCS or antrectomy on the ECL cells. The results show 1) that hyperCCKemia raised the histidine decarboxylase (HDC) activity of the ECL cells in PCS rats but not in control rats, and the CCK-A receptor blockade failed to prevent the enzyme activation; and 2) that PBD prevented the ECL cell hypoplasia and the decrease in HDC activity induced by antrectomy. The findings suggest that under special circumstances endogenous CCK may stimulate the ECL cells.

[Laparoscopic cholecystectomy with the ultrasound dissector]

Due to tissue selectivity the ultrasonic dissector facilitates anatomical clearance even in difficult situations. Although of no advantage in routine laparoscopic cholecystectomies and even more time consuming, it seems to be of considerable value in difficult laparoscopic cholecystectomies and offers more safety for the patient.

Functional and phenotypic analysis of thymocytes in SCID mice. Evidence for functional response transitions before and after the SCID arrest point

Thymocytes from severe combined immune deficient (SCID) mice undergo developmental arrest at an early stage, before most TCR gene rearrangement. They therefore represent a natural test case to assess those aspects of T cell development that are TCR independent. Multiparameter flow cytometry was used to analyze the array of immature phenotypes present in the SCID thymus at steady state, as defined by the markers CD4, CD5, Sca-1, NK1.1, CD44, heat-stable antigen (HSA), and IL-2R alpha. The results suggest a simple developmental block in SCID mice rather than a program of aberrant differentiation. SCID thymocytes displayed efficient, developmentally regulated functional responses. Approximately 20-25% of the cells, mostly within the IL-2R alpha +HSA+CD44low fraction, could be induced to express IL-2. This IL-2 inducibility was highly dependent on IL-1 costimulation, in agreement with the behavior of normal immature thymocytes. These results formally demonstrate that competence to express IL-2 is developed independently of TCR expression or gene rearrangement. Comparison of the response properties of various SCID thymocyte subsets indicated that IL-2 inducibility is first likely to be acquired at an early (Sca-1++CD44++HSAlow) stage. A later functional transition was revealed by comparing patterns of IL-2R alpha regulation in normal and SCID IL-2R alpha +HSA+CD44low thymocytes. The SCID thymocytes uniformly maintained IL-2R alpha expression on in vitro stimulation, whereas only a minority of the normal cells in the corresponding subset could do so unless IL-1 was also added. The SCID arrest point thus appears to separate the IL-2R alpha +HSA+CD44low stage into distinct early (TCR independent) and late phases. Normal cells that progress beyond the SCID arrest point appear to lose, rather than gain, competence to make various responses, even before they leave the IL-2R alpha +HSA+CD44low stage. A model is proposed in which discrete changes in functional competence define novel transitions in early thymocyte development, at least some of which may be linked to TCR-beta gene rearrangement before positive or negative selection.

New advances in vaccine delivery systems

Successful application of the next generation of vaccines will require that protection be induced with a minimal number of administrations, and that a practical approach to inducing immunity at mucosal surfaces be developed. For these reasons, vaccine-containing microspheres were formulated from the biodegradable and biocompatible copolymer poly(DL-lactide-co-glycolide) [DL-PLG]. Subcutaneous immunization of mice with 1- to 10-microns microspheres containing a toxoid vaccine of staphylococcal enterotoxin B (SEB) induced a 500-fold potentiation of the circulating antitoxin response. Strong adjuvant activity was dependent on the microspheres being no more than 10 microns in diameter and required that the antigen was within the particles. The rate of DL-PLG biodegradation is a function of the ratio of lactide to glycolide, and the co-injection of SEB toxoid microspheres formulated with two different DL-PLG ratios stimulated both a primary and an anamnestic secondary antitoxin response. When it was administered by the oral or intratracheal (IT) route, microencapsulated SEB toxoid was found to be effective in the induction of concurrent circulating and disseminated mucosal antibody responses. Female rhesus macaques immunized with a microencapsulated simian immunodeficiency virus (SIV) vaccine produced high levels of circulating anti-SIV antibodies, and following oral or IT boosting, specific antibodies were found in vaginal wash fluids. Vaginal challenge with viable homologous SIV resulted in the infection of three out of four nonimmunized but only one out of seven microsphere-immunized macaques. Thus, DL-PLG microspheres are a promising approach to the delivery of vaccines, combining adjuvant activity with controlled release and effective presentation to mucosally associated lymphoid tissues (MALT).

Functional and phenotypic analysis of thymocytes in SCID mice. Evidence for functional response transitions before and after the SCID arrest point

Thymocytes from severe combined immune deficient (SCID) mice undergo developmental arrest at an early stage, before most TCR gene rearrangement. They therefore represent a natural test case to assess those aspects of T cell development that are TCR independent. Multiparameter flow cytometry was used to analyze the array of immature phenotypes present in the SCID thymus at steady state, as defined by the markers CD4, CD5, Sca-1, NK1.1, CD44, heat-stable antigen (HSA), and IL-2R alpha. The results suggest a simple developmental block in SCID mice rather than a program of aberrant differentiation. SCID thymocytes displayed efficient, developmentally regulated functional responses. Approximately 20-25% of the cells, mostly within the IL-2R alpha +HSA+CD44low fraction, could be induced to express IL-2. This IL-2 inducibility was highly dependent on IL-1 costimulation, in agreement with the behavior of normal immature thymocytes. These results formally demonstrate that competence to express IL-2 is developed independently of TCR expression or gene rearrangement. Comparison of the response properties of various SCID thymocyte subsets indicated that IL-2 inducibility is first likely to be acquired at an early (Sca-1++CD44++HSAlow) stage. A later functional transition was revealed by comparing patterns of IL-2R alpha regulation in normal and SCID IL-2R alpha +HSA+CD44low thymocytes. The SCID thymocytes uniformly maintained IL-2R alpha expression on in vitro stimulation, whereas only a minority of the normal cells in the corresponding subset could do so unless IL-1 was also added. The SCID arrest point thus appears to separate the IL-2R alpha +HSA+CD44low stage into distinct early (TCR independent) and late phases. Normal cells that progress beyond the SCID arrest point appear to lose, rather than gain, competence to make various responses, even before they leave the IL-2R alpha +HSA+CD44low stage. A model is proposed in which discrete changes in functional competence define novel transitions in early thymocyte development, at least some of which may be linked to TCR-beta gene rearrangement before positive or negative selection.

Cloning and sequence of bone morphogenetic protein 4 cDNA from fetal rat calvarial cell

A cDNA clone encoding bone morphogenetic protein 4 (BMP 4) has been isolated from a primary fetal rat calvarial cell cDNA library. Sequencing of this clone has revealed a single open reading frame encoding a 408 amino acid protein. Comparison of 5' noncoding exon 1 portion of this cDNA with that of human bone and prostate BMP4 cDNA shows that BMP4 gene expression may possess tissue specificity.

[Prevention of reserpine induced experimental gastric ulcer in rat with amoxicillin a report of preliminary controlled study]

In recent years, amoxicillin (A) has been proved very effective in clearing helicobacter pylor (HP) and promoting ulcer healing. Is the cure due solely to the clearance of HP? Forty three Wistar rats were randomized into four groups to investigate the efficacy of A in preventing the experimental ulcer induced by reserpine and compare it with that of ranitidine (R) and antacid weishuping (W). A normal saline (NS) group was used as control. The total numbers of ulcer induced per rat for the NS, W, R and A groups were 7.8 +/- 5.1, 2.2 +/- 3.2, 1.0 +/- 1.2 and 2.1 +/- 1.9, respectively. The ulcer indices were 20.8 +/- 13.2, 4.5 +/- 7.7, 2.0 +/- 3.7 and 4.5 +/- 3.9, respectively. No HP was identified. The results indicated that A, R and W were all effective in preventing reserping induced ulcer with no significant difference (P > 0.05); they were significantly more effective than NS (P < 0.05). Since A is not an antacid and no HP existed in the experimental rats, there must be a mechanism of A involved in the prevention of experimental ulcer.

Evidence of L-arginine/nitric oxide pathway in endothelium and smooth muscle of human internal mammary artery

The L-arginine-nitric oxide (NO) pathway was investigated in human internal mammary artery (HIMA) in vitro. HIMA rings were mounted in organ bath, and then incubated in Krebs buffer for 1 to 8 hrs, relaxing agents were tested. Under these conditions, L-arginine (0.1 microM - 1 mM) elicited only minor relaxation after 2 hr incubation, whereas with increased incubation time (4, 6, 8 hrs), the concentration-dependent relaxation to L-arginine increased significantly in endothelium-intact and -denuded vessels. NG-nitro-L-arginine (100 microM) or NG-monomethyl-L-arginine (100 microM) or methylene blue (2.7 microM) partially inhibited L-arginine relaxation. In endothelium-intact HIMA and in both types of rings A23187 (10 microM) and L-arginine (100 microM), respectively, increased the concentration of NO in medium and cGMP content of vascular tissues. These increases were partially inhibited by NG-nitro-L-arginine (100 microM) or methylene blue (2.7 microM).

CONCLUSION

in smooth muscle of HIMA L-arginine-NO conversion is calcium independent, which is different from that in endothelium.

Three-dimensional visualization of the rotavirus hemagglutinin structure

Three-dimensional structures of a native simian and reassortant rotavirus have been determined by electron cryomicroscopy and computer image processing. The structural features of the native virus confirm that the hemagglutinin spike is a dimer of VP4, substantiated by in vivo radiolabeling studies. Exchange of native VP4 with a bovine strain equivalent results in a poorly infectious reassortant. No VP4 spikes are detected in the three-dimensional reconstruction of the reassortant. The difference map between the two structures reveals a novel large globular domain of VP4 buried within the virion that interacts extensively with the intermediate shell protein, VP6. Our results suggest that assembly of VP4 precedes that of VP7, the major outer shell protein, and that VP4 may play an important role in the receptor recognition and budding process through the rough endoplasmic reticulum during virus maturation.

Accumulative effect of two low doses of irradiation in inducing an adaptive response in human lymphocytes

A chromosomal adaptive response to Co-60 gamma-rays in human lymphocytes was observed over a range of 1-20 cGy pre-exposure doses, with 1 cGy giving optimal reduction in chromatid breaks. A 0.5 cGy dose, which in itself did not induce an adaptive response, did so when given twice within the same cell cycle, and the magnitude of the accumulative effect was strongest when there was an interval of 6 h between the two adaptive doses and between the second adaptive dose and a challenge dose. Reductions equivalent in effect to a single 1 cGy dose were seen when a 0.5 cGy dose was given twice. Delivering two 1 cGy doses had no greater effect than did a single 1 cGy dose.

Time-dependent changes in enterochromaffin-like cell kinetics in stomach of hypergastrinemic rats

BACKGROUND

Hypergastrinemia has been claimed to cause first hyperplasia and then dysplasia/neoplasia of enterochromaffin-like (ECL) cells in rat stomach. The growth is thought to reflect an accelerated self replication rate of mature ECL cells. The cytokinetics and the histidine decarboxylase (HDC) activity of the ECL cells were investigated during sustained hypergastrinemia.

METHODS

Hypergastrinemia was evoked by omeprazole (400 mumol.kg-1 x day-1 orally) for up to 1 year. Immunocytochemistry for histamine was used to determine the ECL cell density and combined with [H3]-thymidine autoradiography to establish the labeling index (LI), i.e., the proportion of the ECL cells that has incorporated [H3]thymidine.

RESULTS

The ECL cell density increased progressively for 10-20 weeks in response to the hypergastrinemia and remained at a plateau for the remainder of the study. The hyperplasia was diffuse with additional micronodules at 52 weeks. The ECL cell Ll was maximally elevated after 1-2 weeks and declined to control values after 10-20 weeks of treatment. In contrast, the HDC activity remained elevated for the duration of the study.

CONCLUSIONS

The ECL cell hyperplasia reflects the transiently elevated ECL cell Ll during the early phase but is not associated with an accelerated rate of mitosis during the 10-52 weeks period. Even though with time gastrin seems to loose its ability to sustain a high ECL cell Ll it retains its ability to maintain a high HDC activity.

Topically active ocular carbonic anhydrase inhibitors: novel biscarbonylamidothiadiazole sulfonamides as ocular hypotensive agents

A novel homologous series of bis(carbonyl)amidothiadiazole sulfonamides has been synthesized for structure-activity relationship studies, and initial characterization has been performed. The goal was synthesis of thiadiazole derivatives with appropriate lipid and water solubilities for utility as topically (corneal application) active carbonic anhydrase (CA) inhibitors. This series has solubility properties and pKa which bracket those of acetazolamide--the prototypical CA inhibitor. All of these compounds are active as in vitro CA inhibitors, and are 10-25% as potent as acetazolamide as in vitro enzyme inhibitors. Two of these compounds act as ocular hypotensive agents after topical application of a single dose to the corneas of normotensive New Zealand albino rabbits. The efficacy of the lead compound of this series (in this one model) is approximately equivalent to that of topical CA inhibitors that are presently in clinical trial. None of these novel compounds reacts to an appreciable extent with free sulfhydryl groups (a predictor of toxicity). This family of compounds will be useful for future studies of ocular pharmacokinetics, as well as ocular and systemic effects of topical administration of CA inhibitors. These and future studies may lead to development of thiadiazole sulfonamides useful in the management of glaucoma.

Comparison of semen quality obtained by vibratory stimulation and masturbation

Six normal males underwent both penile vibratory stimulation and masturbation in order to compare the quantity and quality of semen produced by each method. There was no significant difference in the quantity and quality of the ejaculates produced by vibratory stimulation of the penis and masturbation. In addition, biochemical analysis of the seminal fluid collected by both procedures revealed similar values between all specimens for nine organic constituents, seven inorganic constituents and seven metabolic enzymes. None of the subjects demonstrated retrograde flow of semen. These findings indicate that vibratory stimulation is a 'physiological' means of inducing ejaculation, and can produce semen of normal quality.

Acute effects of smoking during modified sham feeding in duodenal ulcer patients. An analysis of nicotine, acid secretion, gastrin, catecholamines, epidermal growth factor, prostaglandin E2, and bile acids

Smoking is associated with an increased incidence of duodenal ulcer with a high relapse rate, and smokers tend to be slow healers. The etiology responsible for this remains unknown, and there is general disagreement as to whether smoking affects gastric secretion. The aim of the present study was to investigate both aggressive and protective factors in response to vagal stimulation induced by modified sham feeding (MSF) in duodenal ulcer patients when smoking versus not smoking. On smoking days, nicotine concentrations in plasma averaged about 15 ng/ml and were extremely high in saliva and gastric juice (> 1300 and > 800 ng/ml, respectively). MSF induced a significant decrease in intragastric pH during non-smoking (p = 0.01) but not during smoking. Acid output 1 h after MSF was lower on smoking than on non-smoking days (p = 0.02), as was volume secretion (p = 0.02). Plasma gastrin concentrations were significantly increased during MSF on non-smoking days (p = 0.04) but not on smoking days, the concentrations during the whole day being lower on smoking days (p = 0.002). Plasma catecholamine levels were unaffected by MSF, whether smoking or not. However, plasma concentrations of noradrenaline decreased during the smoking of a single cigarette (p = 0.03), whereas those of adrenaline were increased on smoking days (p = 0.02). Epidermal growth factor concentrations were decreased in gastric juice after MSF during non-smoking (p = 0.01) but not during smoking. Although prostaglandin E2 (PGE2) concentrations in gastric juice were unaffected by MSF, PGE2 output increased after MSF whether smoking or not, the increment being non-significantly less during smoking (p = 0.09).(ABSTRACT TRUNCATED AT 250 WORDS)

Rescue of infectivity by sequential in vitro transcapsidation of rotavirus core particles with inner capsid and outer capsid proteins

We recently developed an in vitro transcapsidation system in which infectivity of single-shelled (ss) rotavirus particles was successfully rescued (Chen and Ramig, Virology [1993]). Here, we report the rescue of infectivity of rotavirus core particles using virus strain B223 (G serotype 10) as the core donor and strain SA11-4F (G3) as the capsid donor. Core particles of B223 were obtained by CaCl2 treatment of B223 ss-particles followed by isopycnic CsCl gradient centrifugation. Inner capsid protein VP6 of SA11-4F was prepared by CaCl2 treatment of SA11-4F ss-particles, followed by removal of core particles by two rounds of centrifugation. Outer capsid proteins VP4 and VP7 of SA11-4F were prepared by EDTA treatment of ds-particles, followed by three rounds of centrifugation to remove ss-particles and minimize residual infectivity. No infectivity (< 3 PFU/ml) was detectable in any of the donor preparations. Transcapsidated ss-particles were obtained by mixing B223 core particles and a 5-fold excess of SA11-4F VP6 at neutral pH. The formation of transcapsidated ss-particles was confirmed by electron microscopy, protein composition analysis, and density determination. Along with the formation of ss-particles by in vitro transcapsidation, some infectivity was also detected and transcriptase activity was reconstituted. Semi-purified transcapsidated ss-particles were then mixed with SA11-4F outer capsid proteins VP4 and VP7 at acidic pH to obtain transcapsidated ds-particles, as described previously. The formation of ds-like particles was also confirmed by electron microscopy, protein composition, and density determination. As the result of formation of transcapsidated ds-like particles, viral infectivity increased significantly (80-fold) relative to that of transcapsidated ss-particles. The infectivity of transcapsidated ds-particles was neutralized by polyclonal anti-SA11 serum, but not by polyclonal anti-B223 serum. The transcapsidated particles formed small plaques like B223 (core donor), and all the progeny plaques contained B223 genomes. These results demonstrate that the infectivity of rotavirus core particles can be rescued by sequential addition of inner and outer capsid proteins in vitro.