Quantitative autoradiography of angiotensin II receptors in the rat solitary-vagal area: effects of nodose ganglionectomy or sinoaortic denervation

The experiments reported here were designed to examine whether angiotensin II (AII) receptors in the rat solitary-vagal area (SVA) are associated with the neuronal components of the baroreceptor reflex. AII receptors were characterized both in membrane preparations from the rat brainstem and by in vitro autoradiography using the radiolabeled AII antagonist [125I]Sar1,Ile8-AII([ 125I]SI-AII). Saturation analysis of [125I]SI-AII binding to membrane preparations from rat brainstem indicated binding to two high affinity sites (Kd1 0.32 nM and Bmax1 5.10 fmol/mg protein, Kd2 0.99 nM and Bmax2 7.94 fmol/mg protein). The rank order competition by unlabeled angiotensin peptides (SI-AII greater than AII greater than AIII greater than AI) in both membrane preparations and by quantitative autoradiography was consistent with the labeling of the brain AII receptor. Autoradiography of the [125I]SI-AII binding in sections through the SVA revealed that the nucleus tractus solitarius (NTS) and the dorsal motor nucleus of the vagus (DMV) were heavily labeled. Bilateral sinoartic denervation, which disrupts primary baroreceptor afferents, resulted in a small decrease in [125I]SI-AII binding in the rostral and intermediate NTS and DMV. Unilateral nodose ganglionectomy, which disrupts completely the vagal afferent input to the NTS and produces retrograde degeneration of the vagal efferent neurons in the DMV, resulted in a marked decrease in [125I]SI-AII binding at all levels of the ipsilateral NTS and 56% decrease within the ipsilateral DMV. These results indicate that AII receptors within the SVA are distributed heterogeneously, with a large portion associated with vagal afferent fibers in the NTS and vagal efferent neurons of the DMV, and a small but significant portion associated with baroreceptor afferents. The majority of AII receptors in the NTS, however, were not affected by these surgical interventions and therefore appear to be located on intrinsic interneurons or non-vagal afferents in the NTS.

Maximal activities of glutaminase, citrate synthase, hexokinase, phosphofructokinase and lactate dehydrogenase in skin of rats and mice at different ages

The activities of key glycolytic enzymes are, in general, similar at the three different ages of the animals used in this work (very young, adult and old). Glutaminase is present in skin of both mice and rats, but the activity was much lower in adult animals compared to the very young or the old. It is suggested that this activity is important for the provision of nitrogen for the de novo synthesis of purine and pyrimidine nucleotides during the growth of skin in the young animal and for DNA repair in the old animals; it might be important in the adult skin in response to wound healing.

Cloning of a lymphocyte homing receptor reveals a lectin domain

Lymphocytes express cell surface molecules, termed homing receptors, that mediate their selective attachment to specialized high endothelial venules found within secondary lymphoid organs. Previous work has demonstrated that the adhesive interaction between lymphocytes and the endothelium of peripheral lymph nodes appears to involve a lectin-like activity. Moreover, MEL-14, a monoclonal antibody that blocks lymphocyte-peripheral lymph node binding and presumably recognizes the homing receptor mediating this adhesive interaction, appeared to detect the lectin-like receptor. In this paper we describe the cloning of a murine cDNA that encodes the antigen recognized by the MEL-14 antibody. Characterization of the cDNA encoding the putative mouse peripheral lymph node-specific homing receptor shows that it contains a lectin domain that appears to be involved in the binding of lymphocytes to peripheral lymph node endothelium, thus defining a new type of cellular adhesion molecule. This result supports a novel mechanism for the distribution of lymphocyte populations to various lymphoid organs.

Tree LANs with collision avoidance: protocol, switch architecture, and simulated performance

Packet collisions and their resolution create a performance bottleneck in random access LANs. A hardware solution to this problem is to use collision avoidance switches. These switches allow the implementation of random access protocols without the penalty of collisions among packets. We describe the designs of some tree LANs that use collision avoidance switches. The collision avoidance LANs we describe are broadcast star and CAMB tree (Collision Avoidance Multiple Broadcast tree). We next present a possible implementation of a collision avoidance switch using currently available photonic devices. Finally, we show the performance of broadcast star and CAMB tree networks using simulations.

Effect of renal mass reduction on kidney tissue concentration of gentamycin following a single dose

Controversy exists concerning the effect of pre-existing renal disease on aminoglycoside nephrotoxicity. Since nephrotoxicity appears to be related to gentamycin concentration in the renal tissue, we studied the effect of renal mass reduction on renal tissue gentamycin concentration. Four groups of male Sprague-Dawley rats, who had undergone progressive renal mass reduction, were studied after injection with a single dose of gentamycin. As expected, serum gentamycin concentration was increased in nephrectomized animals and showed significant inverse correlation with the weight of the residual renal tissue. However, urinary gentamycin secretion rate was proportional with the weight of the residual renal tissue. Renal tissue gentamycin concentrations in the nephrectomized animals were significantly higher than that found in the sham-operated controls. The data indicate that renal tissue gentamycin concentration attained after a single dose of the drug is higher in the presence of reduced renal mass.

Clinicopathologic studies in childhood pancreatitis

In a review of pediatric autopsies from 1951 to 1985, we identified 40 cases in which pancreatitis was diagnosed pathologically. Twenty-six of these patients were under 4 years of age, and the male-to-female ratio was 1.5. Six groups of patients were identified: 10 with hepatobiliary disease, including 9 with biliary atresia; 7 with immunosuppressive therapy for tumors (n = 2), leukemia (n = 4) and aplastic anemia (n = 1); 6 with viral infections; 8 with congenital anomalies, including congenital heart disease (n = 3); and 9 with miscellaneous problems. Several patients had surgery and various intercurrent complications. Clinical features attributable to the pancreatitis included vomiting or excessive nasogastric drainage (60%), pleural effusions (40%), and abdominal pain (25%). However, the diagnosis was suspected clinically in only 5 of 40 patients. Our findings suggest several pathogenic mechanisms exist for childhood pancreatitis: biliary obstruction, infections, drug toxicity, immunosuppression (acting in synergy with drug toxicity, trauma, and low-flow states resulting from shock, heart failure, and vasculopathy.

High-performance liquid chromatography of amino acids, peptides and proteins. LXXXIV. Application of derivative spectroscopy to the study of column residency effects in the reversed-phase and size-exclusion liquid chromatographic separation of proteins

The influence of column residency times on the reversed-phase gradient elution behaviour of human and bovine growth hormones has been investigated using on-line photodiode array spectroscopic detection. Stationary phase induced effects on protein conformation were monitored by changes in the maxima to minima ratio of the second derivative spectrum of the eluted protein. Significant changes in the second derivative ratio of the unmodified and the fully reduced and alkylated protein were observed following long incubation times, i.e. t(dwell) greater than 15 min, at the stationary phase surface in the presence of 0.1% trifluoroacetic acid before elution with a 0-75% aqueous acetonitrile gradient. The application of multi-wavelength detection in the study of equilibrium unfolding of growth hormones in urea by size-exclusion chromatography was also investigated. On-line photodiode array instrumentation and derivative spectra rationing was employed to monitor tertiary and quaternary structural changes associated with protein denaturation during a chromatographic separation. These studies clearly demonstrate the powerful detection capabilities of such instrumental approaches for the on-line evaluation of both stationary phase surface and/or mobile phase mediated changes in protein conformation.

Hematologic changes occurring with cardiac catheterization

The composition of the blood influences rheology and therefore might affect hemodynamics. During cardiac catheterization and angiography, blood is sampled and contrast media, fluid, and heparin are administered. To determine the effects of these perturbations on the blood cell count and coagulation, femoral vein samples were obtained at the beginning of cardiac catheterization, before heparin, 4,000 U; at the end, before protamine reversal; and after protamine, 40 mg, was administered. At the end of catheterization, 41 +/- 3 min after heparin administration, all cellular constituents were significantly lower than control: White (W) blood cells (BC) were 8.1 +/- 2.7% lower (P less than 0.05), red (R) BC, 10 +/- 1.8% (P less than 0.05), and platelets (P) 10.9 +/- 1.5% (P less than 0.05). Protamine lowered further WBC by 23 +/- 4% (P less than 0.05 and P) by 14 +/- 2% (P less than 0.05), but did not change RBC (4.13 +/- 0.20 x 10(6) to 4.25 +/- 0.23 x 10(6]. Before protamine administration, all patients had a partial thromboplastin time (PTT) 1.5 times the control value and ten of 13 patients had a value greater than 100 sec. Although four of 13 patients had an incomplete reversal of PTT after protamine, none suffered an untoward event. In conclusion, cardiac catheterization produces changes in the cellular composition of the blood, and such changes might influence hemodynamic measurements.

Lack of effect of chronic carbamazepine on brain somatostatin in the rat

We investigated the effects of chronic carbamazepine treatment in rats on brain somatostatin. Following 12 days of carbamazepine treatment, no changes in somatostatin levels were found in any of the brain areas examined which included: amygdala, hippocampus, caudate-putamen, median eminence, arcuate nucleus, nucleus accumbens, nucleus interstitialis of the stria terminalis, nucleus periventricularis, parietal cortex, and occipital cortex. Thus, carbamazepine in low doses does not affect basal levels of brain somatostatin in the rat, in contrast to the previous reports of decreased somatostatin in the cerebrospinal fluid of affectively ill patients.

Urinary digoxin-like immunoreactive substance in pregnancy. Relation to urinary electrolytes

High concentrations of digoxin-like immunoreactive substance (DLIS) have been identified in amniotic fluid and in blood during pregnancy. In this study, urine from healthy women was analyzed for DLIS during pregnancy and following delivery, and levels were related to various clinical and urinary findings. Urinary DLIS increased progressively during pregnancy, having a linear relation to gestational week (DLIS = 0.032 week + 0.46, Syx = 0.52, r = 0.46, p less than 0.01), and fell to nonpregnant values during the first postpartum day. The urinary DLIS level correlated with urinary creatinine (r = 0.50, p less than 0.01) and urinary calcium (r = 0.56, p less than 0.01) levels. When adjusted for the gestational week, the urinary DLIS level also correlated with urinary potassium (r = 0.48, p less than 0.01), creatinine (r = 0.55, p less than 0.01), and magnesium (r = 0.55, p less than 0.01) levels. After adjustment for the urinary creatinine level, only the relation of urinary DLIS and urinary calcium levels remained significant (r = 0.44, p less than 0.05). The urinary DLIS level was not found to be related to systemic blood pressure. The ratios of sodium to potassium (r = -0.43, p less than 0.05) and calcium to magnesium (r = 0.37, p less than 0.05) were also related to gestational week but were independent of the urinary DLIS level. Thus, urinary DLIS increases progressively during pregnancy and falls to nonpregnant values on the first postpartum day, the urinary DLIS level can be related to urinary creatinine, urinary potassium, and urinary magnesium levels, and when adjusted for the urinary creatinine level, the urinary calcium level relates independently to the urinary DLIS level.

[A rare cause of heart failure: hypocalcemic cardiopathy]

In this paper, the authors present the case of hypocalcemic cardiopathy observed in a female patient who underwent thyroidectomy which was complicated post-operatively by the development of hypoparathyroidism. Two attacks of heart failure experienced by this patient were improved by the administration of calcium in combination with digitalis treatment. A study of cases published in the medical literature reveals that this condition is a rare cause of heart failure which develops only in the course of chronic hypocalcemia, with few neuromuscular clinical manifestations. The dual negative inotropic and hypovolemic effects caused by hypocalcemia explain the efficacy observed with the administration of calcium therapy, while the usual symptomatic treatment of this condition is inadequate.

[Surgical treatment of hepatoma on a cirrhotic liver]

From January 1, 1975 to July 1, 1984, 37 patients with a tentative diagnosis of hepatocarcinoma on cirrhosis were operated upon. There were 34 men and 3 women, aged from 32 to 82 years (mean: 60 years). The diagnosis of cirrhosis rested either on a history of liver failure associated with clinical and biochemical signs of hepatocellular dysfunction (4 cases), or on a positive liver biopsy (5 cases). In 20 cases the diagnosis was suspected on account of abnormal liver function tests, but in 8 patients it was revealed by macroscopic examination of the liver during surgery. Cirrhosis was attributed to chronic alcoholism in 25 cases, haemochromatosis in 11 cases and positive HBs antigen in 7 cases. The diagnosis of hepatocarcinoma, suggested by altered general condition or recent pain, rested on the finding of a tumoral image at scintigraphy (16 cases), ultrasonography (19 cases), computed tomography (7 cases), arteriography (17 cases) or laparoscopy (7 cases). In only 7/32 patients was the alpha-foetoprotein level higher than 500 ng/l. Surgery confirmed the diagnosis of hepatocarcinoma in every case but that of cirrhosis in only 14/37 cases; 10 patients had lesion of hepatic fibrosis and 1 had regenerative nodular hyperplasia. In 10 cases no accurate histological diagnosis could be made since the liver tissue sample had been taken too close to the tumour. The finding of normal liver tissue shows that one should not refrain from operating merely because the diagnosis of cirrhosis rests on clinical grounds. Since 1979, surgical treatment consists in an attempt to excise the tumour. Per-operative mortality is the same with excision surgery (21%) as with exploratory or palliative surgery (17%). Fourteen excisions were performed (i.e. aresectability rate of 38% for the series): 2 liver transplantations, 2 right hepatectomies, 2 left hepatectomies, 2 left lobectomies, 2 bisegmentectomies and 3 tumorectomies. The survival rate of 2 years was 27%, as opposed to 5% with exploratory or palliative surgery. Systematic monitoring of cirrhosis with ultrasonography should result in early diagnosis of hepatocarcinoma at a stage where limited hepatic excision is possible and the chances of surviving are highest.

Use of an antibody to characterize and determine the role of the major Met-tRNAf deacylase from rabbit reticulocyte ribosomes

Inhibition of polypeptide chain initiation in rabbit reticulocyte lysate by phosphorylation of eukaryotic initiation factor-2(alpha) results, secondarily, in the enzymatic deacylation of Met-tRNAf on the 48 S initiation complexes that accumulate. We have prepared an antibody to a highly purified preparation of the major Met-tRNAf deacylase activity on rabbit reticulocyte ribosomes, termed deacylase II. Antibody, but not similarly purified normal IgG, completely neutralizes the activity of Met-tRNAf deacylase II and has no effect on Met-tRNAf deacylase I, a separate, minor, reticulocyte activity with the same substrate specificity but very different physical and enzymatic properties, strongly suggesting that deacylase I and II are distinct proteins. We partially purified Met-tRNAf deacylase activities from rabbit liver, myocardium and bone marrow ribosomes and found them to be similar to each other and to reticulocyte deacylase I in their enzymatic properties and insensitivity to anti-deacylase II, suggesting that deacylase I may be a general form of this enzyme, present in many cells, while deacylase II may be induced specifically during erythroid differentiation. Addition of the antibody to reticulocyte lysate incubated in the absence of hemin or presence of hemin plus 0.1 microgram/ml poly(I X C) did not reverse the inhibition of protein synthesis but did reduce the rate of turnover/utilization of Met-tRNAf and increase the level of Met-tRNAf bound to 48 S initiation complexes, demonstrating that the deacylase does not directly inhibit protein synthesis under these conditions but does mediate the deacylation, loss, and thus greater than expected turnover of Met-tRNAf in the 48 S complexes that accumulate.

Quantification of cerebral infarct size by creatine kinase BB isoenzyme

Creatine Kinase BB isoenzyme (CKBB) has been shown to rise in the serum and CSF following acute cerebral injury. To test the hypothesis that brain infarct size could be estimated from the appearance and disappearance of CKBB in the serum and CSF, strokes of varying size were produced in twelve mongrel dogs by silastic emboli. The rate of disappearance, Kd of CKBB (-.00732 +/- 0.001 min-1 mean +/- SE, N = 8) was determined by injecting purified CKBB (25 IU) intravenously then measuring its disappearance. Following the embolic stroke, serum samples were taken hourly for 24 hours and then at intervals for up to 160 hours for measurement of CKBB by radioimmunoassay until the animals were sacrificed. The brains were then removed, fixed in formalin, cut in 2 mm sections and photographed. The area of the infarct was measured using high pad digitizer interfaced with an Apple computer. The infarct size was then calculated from the area and thickness. Using a one-compartment mathematical model, the infarct size was estimated from the amount of CKBB appearing in the serum, the Kd of CKBB, and the amount of CKBB depleted from tissue. The computed infarct size correlated well (r = 0.94) with the measured infarct size. This model may have value in testing therapeutic modalities in the intact animal.

Analyses of vegetables from the highlands of Papua New Guinea

Ten vegetable foods of the highlands were analysed for crude protein, amino acids and trypsin inhibitor. Pandanus nut, lima bean, fern, greens, pitpit and choko had good to acceptable crude protein contents and the proteins of fern, pitpit, Rungia klossii and Indian mustard were of good quality. Lima beans had a very high content of trypsin inhibitor and all others had small or zero amounts, including fern, which is used at pig feasts and hence does not contribute to pig bel.

Comparison of improved precipitation methods for quantification of high-density lipoprotein cholesterol

We compared the standard Lipid Research Clinics heparin-Mn2+ (46 mmol/L) method and five improved precipitation methods for quantification of high-density lipoprotein (HDL) cholesterol. Three of these methods--a dextran sulfate-Mg2+ procedure, reported as a Selected Method, a modified heparin-Mn2+ (92 mmol/L) method, and a modified phosphotungstate-Mg2+ procedure--all gave similar results. Three other methods--the standard heparin-Mn2+ (46 mmol/L) method and two polyethylene glycol methods (75 g/L or pH 10 reagent at 100 g/L final concentrations)--gave slightly higher values for HDL cholesterol. Addition of NaCl or glucose to specimens did not significantly change protein precipitation. In terms of sedimentation effectiveness with hypertriglyceridemic specimens, the methods were ranked in the following order: polyethylene glycol (pH 10, 100 g/L) greater than dextran sulfate-Mg2+ greater than heparin-Mn2+ (92 mmol/L) = polyethylene glycol (75 g/L) greater than phosphotungstate-Mg2+ greater than heparin-Mn2+ (46 mmol/L).

Comparison of improved precipitation methods for quantification of high-density lipoprotein cholesterol

We compared the standard Lipid Research Clinics heparin-Mn2+ (46 mmol/L) method and five improved precipitation methods for quantification of high-density lipoprotein (HDL) cholesterol. Three of these methods--a dextran sulfate-Mg2+ procedure, reported as a Selected Method, a modified heparin-Mn2+ (92 mmol/L) method, and a modified phosphotungstate-Mg2+ procedure--all gave similar results. Three other methods--the standard heparin-Mn2+ (46 mmol/L) method and two polyethylene glycol methods (75 g/L or pH 10 reagent at 100 g/L final concentrations)--gave slightly higher values for HDL cholesterol. Addition of NaCl or glucose to specimens did not significantly change protein precipitation. In terms of sedimentation effectiveness with hypertriglyceridemic specimens, the methods were ranked in the following order: polyethylene glycol (pH 10, 100 g/L) greater than dextran sulfate-Mg2+ greater than heparin-Mn2+ (92 mmol/L) = polyethylene glycol (75 g/L) greater than phosphotungstate-Mg2+ greater than heparin-Mn2+ (46 mmol/L).

Primary structure of the soybean nodulin-23 gene and potential regulatory elements in the 5'-flanking regions of nodulin and leghemoglobin genes

The nodulin-23 gene of soybean is one of the most abundantly transcribed genes induced during symbiosis with Rhizobium. Using a plasmid (pNod25) from a nodule cDNA library, we have isolated the nodulin-23 gene from a soybean genomic library. Nucleotide sequence analysis of the cDNA and of the genomic clone indicated that the coding region of this gene is 669 bp long and is interrupted by a single intron of about 530 bp. The deduced protein sequence suggests that nodulin-23 may have a signal sequence. The 5'-flanking sequence of two other nodulin genes, nodulin-24 encoding for a membrane polypeptide and one of the leghemoglobin genes (LbC3), were obtained. Comparison of these sequences revealed three conserved regions, one of which, an octanucleotide (GTTTCCCT), has 100% homology. The conserved sequences are arranged in a unique fashion and have a spatial organization with respect to order and position, which may suggest a potential regulatory role in controlling the expression of nodulin and leghemoglobin genes during symbiosis.