Control of pilus expression in Neisseria gonorrhoeae as an original system in the family of two-component regulators

We have previously reported the identification of two genes, pilA and pilB, which act in trans to regulate pilus expression in Neisseria gonorrhoeae. Here we show that PilA and PilB have amino acid sequence similarities with members of the two component 'sensor-regulator' family of proteins. PilB has homology with histidine kinase sensors. Alkaline phosphatase fusions to the predicted sensor and transmitter domains are described. Their PhoA activity and cellular location suggest that PilB is inserted in the cytoplasmic membrane and predict periplasmic and cytoplasmic locations for the sensor and the transmitter domains, respectively. PilA has homology with response regulators in its N-terminal part, and with components of the eukaryotic protein secretory apparatus (SRP 54 and SRP receptor) as well as two Escherichia coli gene products in its C-terminal part. In particular, it contains a putative GTP-binding site. Mini-transposon insertions into different regions of pilA were obtained. The phenotypes and genotypes of these mutants and preliminary biochemical studies of the gene products of two of these mutants lend further support to the hypothesis that PilA is a DNA-binding response regulator and confirm that it participates in an essential function in the bacterium.

Improvement of Radioactive Colloid Binding by Tumor Cells

Treatment of P388 leukemia cells with poly-DL-lysine (Poly-lys) considerably increases the binding of colloidal chromic phosphate (32P). This augmentation of the number of particles that are bound is in direct relationship with Poly-lys concentration, and very significantly with its degree of polymerization. Treatment with Poly-lys molecular weight 77,000 shows a 100% increase of binding with 200 μg and of 50% with 100 μg. Poly-lys M.W. 8,000 presents no significant increase, and for the other molecular weights the binding is intermediate.

Ventricular couplets in the young: prognosis related to underlying substrate

Ventricular couplets may be a risk factor for sudden death in adults, but their prognosis in children is unknown. From 1981 to 1987 104 patients, mean age 13.2 years (0.2 to 37 years), had ventricular couplets on a 24-hour electrocardiogram (ECG) (Holter monitor) and on follow-up with a second Holter (mean, 2.5 years). Of the 104 patients, 22 had a normal heart and 82 had an abnormal heart. Patients with a normal or an abnormal heart did not differ in incidence or severity of symptoms (patients with a normal heart had 17 instances of palpitations and none of syncope; patients with an abnormal heart had 49 instances of palpitations, six of dizziness, and none of syncope). Number of ventricular couplets was higher in patients with a normal heart (33 +/- 50/day: mean +/- 1 SD) than in those with an abnormal heart (17 +/- 15/day; p less than 0.05). Of the 22 patients with a normal heart, 11 underwent an electrophysiologic study (EPS); none had inducible ventricular tachycardia. After mean follow-up of 29.7 months, all 22 patients with a normal heart were alive without ventricular tachycardia; 6 of 22 were treated for palpitations, with complete suppression of couplets in two. In 11 of 16 untreated patients with a normal heart, ventricular couplets disappeared spontaneously. Of the 82 patients with an abnormal heart, 32 had an EPS: nine (28%) had sustained ventricular tachycardia, 16 (50%) had nonsustained ventricular tachycardia, and seven (22%) had no inducible ventricular tachycardia. ECG criteria and hemodynamic status were of limited value in predicting inducibility of ventricular tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

Dielectric properties of gelatine phantoms used for simulations of biological tissues between 10 and 50 MHz

The use of gelatine phantoms for simulating the dielectric properties of human tissues is suggested. These phantoms are mainly made of gelatine and water and are therefore readily prepared at a low cost. They can be poured into moulds and adopt various shapes depending on the organ to be simulated. In addition, their preservation is not critical. We have studied, at 10, 27 and 50 MHz, the variations of relative permittivity and conductivity as a function of temperature between 15 and 50 degrees C. What is shown is that those values vary both as a function of gelatine concentrations and as a function of temperature. For example, at 37 degrees C and 27 MHz, variations of relative permittivity from 87 to 100 and variations of the conductivity from 0.27 to 0.45 S/m for concentrations of 10% to 40% are observed. At the above frequency, the permittivity of human and animal tissues range between 95 and 180 and the conductivity between 0.4 and 0.6 S/m. Furthermore, the addition of sodium chloride at variable concentrations enables both conductivity and permittivity values to be modified. We propose, as 'muscle-equivalent' phantoms at 27 MHz, a phantom consisting of 20% gelatine with an electrical conductivity from 0.27 to 0.48 S/m and a relative permittivity from 90 to 93 at temperatures between 15 and 50 degrees C. These gelatine, water and sodium chloride phantoms are adapted for easy and cheap simulation of most human tissues in a temperature range from 15 to 50 degrees C, for frequencies from 10 to 50 MHz.

3M dwarfism: a study of two further sibs

Two sibs are reported with clinical and radiological features of the 3M syndrome. The differential diagnosis is discussed, particularly with regard to Russell-Silver syndrome.

Practical interstitial method of heating operating at 27.12 MHz

A practical interstitial capacitive method of heating using thin flexible coated electrodes operating at 27.12 MHz is described. Advantages compared to classical interstitial methods are: uniform heating, control of the inserted length, compatibility with curie therapy, simplicity and low cost. The electrode geometry could be designed according to tumour site and volume. Restriction of longitudinal heating to a part of the wire is also possible. A simple matching circuit can be connected to the active wires to obtain a standing wave ratio (SWR) of less than 1.5. Individual power regulation of the electrode should be used and is feasible at this frequency. Numerical, experimental and clinical results demonstrate the practical value of this method.

Pilin expression in Neisseria gonorrhoeae is under both positive and negative transcriptional control

We have identified two closely linked genes, pilA and pilB, which act in trans on the pilin promoter. pilA-pilB map downstream of expression loci pilE1 and opaE1 in the gonococcal chromosome. Subcloning data indicate that pilB acts negatively on the pilin promoter, and insertional inactivation of pilB results in hyperpiliated gonococci. A pilA clone activates the pilin promoter in Escherichia coli, and a pilA-/pilA+ heterodiploid gonococcus exhibits a P- phenotype. Our inability to obtain simple pilA- mutants strongly suggests that pilA is an essential gene in the gonococcus. In an in vitro coupled transcription/translation system, inserts spanning the pilA and pilB region direct the synthesis of two proteins of 40 and 58 kd. DNA sequence analysis shows that the pilA and pilB loci encode proteins of 38.6 kd (with a putative DNA binding domain) and 57.9 kd respectively. The pilA and pilB genes are in opposite orientation relative to each other, and the 5' ends of the two genes overlap. We discuss how these two loci may interact to control pilin expression in the gonococcus.

DNA transformation leads to pilin antigenic variation in Neisseria gonorrhoeae

Many pathogenic bacteria express pili (fimbriae) on their cell surfaces. These structures mediate binding of bacteria to host tissues, and may also be involved in other aspects of pathogenesis. Neisseria gonorrhoeae pili are mainly composed of a single protein, pilin, whose expression is controlled at chromosomal expression loci (pilE). An intact pilin gene and promoter sequences are only found at pilE. Strain MS11 contains two expression sites (pilE1 and pilE2), whereas several of its derivatives and other clinical isolates contain only one. Silent pilin loci (pilS1-pilS7) contain truncated variant pilin genes lacking the promoter and conserved pilin gene sequences. Pilin antigenic variation in N. gonorrhoeae occurs by DNA recombination between one of he silent partial variant gene segments in pilS and an expressed pilin gene in pilE. The recombination reactions are nonreciprocal, and therefore the mechanism has been classified as gene conversion. We report that much of the recombination between pilin loci actually occurs after transformation of living piliated cells by DNA liberated from lysed cells within a population. This constitutes a new molecular mechanism for an antigenic variation system, as well as the first specific function for a DNA transformation system.

[Effects of intravenous nicardipine on blood pressure, hemorheology platelet function in arterial hypertension. Dose-effect relations]

In arterial hypertension, hyperviscosity with hemorheological disturbances and platelet dysfunction may play a role in the prognosis and complications of the disease. We studied the effects of Nicardipine (NIC) on these blood disturbances in a group of 21 untreated patients with essential hypertension, aged 25 to 70 years (SBP/DBP = 185 +/- 28/105 +/- 17 mmHg). During one hour before and 4 hours after the IV injection of single doses of 5, 7.5 or 10 mg NIC over 5 min, blood pressure was recorded automatically (Dinamap). Hemorheological variables and platelet function were studied before and 30 min, 3 h and 24 hours after the injection. NIC lowered blood pressure and increased heart rate significantly (At 5 min, SBP = -24 mmHg; DBP = -18 mmHg; HR = +22 b/min). These effects were dose-dependent with rapid onset and short duration (less than 2 hrs). NIC decreased plasma viscosity from 1.36 +/- 0.08 to 1.30 +/- 0.07 Cst; p less than 0.01, whole blood viscosity from 22.4 +/- 2.8 to 20.7 +/- 1.5 mPas; p less than 0.05 for gamma = 0.512 s-1, and erythrocyte filterability with the Ca++ ionophore A 23187 from 16.3 +/- 3.8 to 13.5 +/- 3.1; p less than 0.01. Platelet aggregation with ADP was unchanged, but aggregation with A 23187 decreased from 46.9 +/- 21.2 to 31.3 +/- 25.6; p less than 0.05, as well as plasma levels of beta-thromboglobulin (71.2 +/- 29.8 to 55.4 +/- 24.3 ng/ml; p less than 0.02) and platelet generated malonaldehyde (7.2 +/- 1.8 to 6.7 +/- 1.4 nM/10(9) platelets; NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Stroke risk in patients with carotid stenosis

In 242 neurologically symptomless patients with at least one non-occlusive carotid stenosis on ultrasonography (continuous wave doppler and echotomography-B mode imaging) 171 carotids showed 0-50% stenosis, 150 showed 50-75% stenosis, and 78 showed more than 75% stenosis. The mean follow-up was 29.4 months, with stroke and death as end points. Of the 56 deaths 2 were causally linked to a stroke (crude annual mortality index 9.57%). Of the 10 strokes 7 were judged to be infarctions in carotid territory. 7 out of 20 patients with transient ischaemic attacks (TIA) had ischaemic symptoms definitely related to carotid territory. The crude annual indices of specific stroke or TIA were 0.45% for nonstenotic carotid, 0.23% for 0-50% stenosis, 2.48% for 50-75% stenosis, and 1.71% for 75-99% stenosis. Stenoses of greater than 50% were associated with more ischaemic events than were lesser degrees of narrowing (p less than 0.01).

[Measurement by Doppler echocardiography of the pulmonary arterial pressure in children with ductus arteriosus. Simultaneous Doppler and hemodynamic study]

The aim of this study was to evaluate Doppler echocardiography in the non invasive assessment of pulmonary artery pressures in children with patent ductus arteriosus. Systolic pulmonary artery pressure was measured simultaneously at cardiac catheterisation and by pulsed Doppler in 11 children (mean age 1.8 +/- 2 years) with patent ductus arteriosus alone (6 cases) or associated with a malformation of the heart or great arteries (5 cases). Doppler assessment of systolic pulmonary artery pressure was performed by subtracting the value of the maximal pressure gradient between the aorta and pulmonary artery from the systolic systemic pressure measured simultaneously by sphygmomanometry. The maximal pressure gradient between the aorta and pulmonary artery was calculated using the modified Bernouilli formula and the maximal velocity (v) of the shunt flow (gradient = 4 v2). Ductal flow was recorded from the suprasternal approach by direct interrogation of the patent ductus visualised by 2D echocardiography. The systolic pulmonary arterial pressure measured by catheterisation ranged from 21 to 82 mmHg (mean 58 +/- 21 mm Hg) and by pulsed Doppler from 20 to 89 mm Hg (mean 56 +/- 24 mm Hg) (correlation r = 0.94). This study illustrates the value of Doppler echocardiography in the assessment of systolic pulmonary artery pressures in children with patent ductus arteriosus.

[Hemodynamic effects of an alpha-blocking vasodilator in cardiac insufficiency caused by left-right shunt in children]

The acute haemodynamic effects of an alpha-blocking vasodilator, nicergoline, observed during cardiac catheterisation were studied in 9 babies and 1 infant (mean age 11 months) with severe cardiac failure due to a large left-to-right interventricular shunt. Nicergoline was administered intravenously at a dose of 0.05 mg/kg/mn to 0.2 mg/kg/mn to lower mean systemic blood pressure by at least 10 mmHg. No significant changes in heart rate or in right and left atrial pressures were observed. On the other hand, mean systemic and pulmonary arterial pressures fell by 16% (p less than 0.001) and 13% (p less than 0.01) respectively. The ratio of pulmonary and systemic flow (Qp/Qs) decreased in 8 patients by an average of 21% (p less than 0.002). This fall was accompanied by a parallel reduction in oxygen concentrations of pulmonary arterial blood (16%) compared with mixed venous blood. However, the Qp/Qs ratio increased in the other 2 patients by over 50%. In the group of 8 patients in which the left-to-right shunt decreased, the ratio of pulmonary to systemic resistance (Rp/Rs) increased by 33% (p less than 0.002) whilst this value fell by 36% in the 2 patients in whom the volume of the shunt increased. There were no discriminatory parameters between the two groups with regards to age, pulmonary artery pressures, the volume of the shunt (Qp/Qs) or level of pulmonary resistances (Rp/Rs) to explain the variability of the therapeutic response on the left-to-right shunt.(ABSTRACT TRUNCATED AT 250 WORDS)

Hyperthermia and cytotoxic drugs. Possible use of lanthanum as a potentiator of hyperthermia

Recent studies indicate that differences in membrane fluidity may account for differences of thermal sensitivity. This possibility was studied by using lanthanum, a trivalent cation which is known to displace calcium in a number of biological systems, to modify the structural framework of cell membranes and consequently their biological properties. With Ehrlich ascites cells trypan blue exclusion uptake of 86Rb, 42K and 45Ca, indicate an increase of plasma cell permeability by La3+. The reduction of 86Rb and 42K uptake by tumour cells with La3+ appears to be independent of temperature. The increase of 45Ca2+ influx in the presence of lanthanum plus hyperthermia seems related to an important loss of cell viability. The enhancement of hyperthermia lethality by concentrations of lanthanum over 0.5 mM after 2 h at 44 degrees C has been demonstrated using HeLa S3 cells using a standard cloning technique. In vivo experiments have been performed on C3H mice bearing rhabdomyosarcoma using ultrasound heating at 44-46 degrees C. The results show a remarkable inhibition of tumour growth and a significant increase of the survival time after only one hyperthermia session of 30 min combined with one intratumoural injection of 1 mM lanthanum chloride.

[Medium-term results of 200 consecutive systematic operations for revascularization of the anterior interventricular artery by the internal mammary artery]

This study presents the preliminary results of systematic revascularisation of the left anterior descending (LAD) by the internal mammary (IM) artery. Between 1981 and 1983, 200 IM bypass procedures were performed (88.5% of bypassed LAD arteries during the same period). With experience, the contraindications of IM bypass surgery progressively decreased (none in the latter 100 cases). The IM bypass grafting was an isolated procedure in 35% of cases and associated with one or more saphenous vein (SV) bypass grafts in 64.5% of cases with an average of 1.9 grafts per patient. The surgical results were better than those of SV bypass grafting alone in the period 1978-1980 with a mortality of 2.5% and a perioperative infarction rate of 2.5% compared to 4.3% and 7% respectively. The medium term results (average follow up 2.5 years) show that more patients undergoing IM bypass surgery were asymptomatic (75%) than those undergoing SV bypass (46%). However, the patients operated more recently by IM bypass benefitted from the latest technical advances in bypass surgery. An unselected sample of 55 volunteers (out of 90 recalled patients) underwent angiography at 1 year. The patency rate was 93% with a very satisfactory angiographic appearance of the graft in nearly all patients suggesting the likelihood of a good long term result. It was possible to demonstrate graft patency by Doppler ultrasound and digitised intravenous angiography in some cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Preliminary technical, experimental and clinical results of the use of the HPLR 27 system for the treatment of deep-seated tumours by hyperthermia

Based on the theoretical deep penetration of radio frequencies, we have developed several 27.12 MHz ridged wave guides, with large apertures, and filled with circulating deionized water. Different low impedance matching networks have been tested and a 0-800 W power generator has been designed for this particular clinical use. This can be driven easily by a microcomputer which is used to regulate the temperature at depth by varying the sequencing time and/or by adjusting the RF power. The complete system, known as HPRL 27, is manufactured by Sairem Ets. Studies of the spatial power density distributions show a relatively homogeneous RF field for an aperture greater than 30 X 14 cm. Preliminary heating patterns studied in phantoms indicate the possibility of treating volumes greater than 2000 cm3 within the 50 per cent isotherm. Maximum heating is observed between 2 and 5 cm deep with passive cooling, and between 3 and 6 cm deep with active cooling, in which case the 50 per cent isotherm is situated between 2 and 10 cm deep. Preliminary phase I clinical results on 20 patients with pelvic or thoracic carcinomas show the possibility of heating deep-seated tumours to above 42 degrees C with a good patient tolerance. Temperature is controlled by implantable catheters or in the case of pelvic heating, by inserting catheters into the vagina, the rectum and the bladder. This new device is well adapted for the treatment of pelvic tumours.

[Development of urea, creatinine and creatinine clearance as a function of age and sex]

Serum urea and creatinine concentrations were determined in 150 healthy subjects. The formula of Cockcroft and Gault was used in order to calculate creatinine clearance. Such estimation of creatinine clearance is widely used as a parameter for individualization of dosage of drugs secreted primary via the kidneys. The effects of age and sex were then assessed on serum urea, serum creatinine and on creatinine clearance.

Tumor uptake of high and low molecular weight fractions from 67Ga-citrate labelled blood plasma

Blood plasma from tumor-bearing rats was incubated with 67Ga-citrate, and two fractions of high molecular weight (proteins) and low molecular weight were isolated by dialysis and by gel-filtration chromatography. Both fractions showed a different in vivo uptake by DS-sarcoma-bearing animals, the high molecular weight fraction being accumulated to a lesser extent. Compared to 67Ga-citrate the low molecular weight fraction showed a different uptake which for most tissues was significatively higher. This behavior suggests the presence of 67Ga in chemical forms other than citrate in the low molecular weight fraction. The lower uptake of the blood protein fraction is discussed.

On the mechanisms of 67Ga and 59Fe uptake by tumors

The uptake of 67Ga-citrate and 59Fe-citrate in the presence or absence of gallium and iron carriers, was studied on DS-sarcoma-bearing rats. Differences of uptake pattern were observed with both radionuclides. The tumor uptake of 67Ga is greatly affected by both carriers while 59Fe uptake is independent of the presence of carriers. The role of isotopic dilution, ionic competition, and the probable presence of high and low affinity binding sites in this phenomenon are discussed.

Enhancement of hyperthermia lethality by Lanthanum

The authors have studied the effects of La3+ during hyperthermia on tumor cells, Trypan blue exclusion and 86Rb release from previously labeled Ehrlich and DS carcinosarcoma ascites cells, indicate an increase of plasma membrane permeability by La3+ as a function of the hyperthermic level. The enhancement of hyperthermia lethality by concentration of Lanthanum over 0.5 mM after 2 hours at 44 degrees C has been demonstrated on HeLa S3 cells using a well known cloning technique. In vivo experiments have been performed on Rhabdomyosarcoma C3H bearing mice using an ultrasound heating technique at 44-46 degrees C. The preliminary in vivo results show a remarkable tumor growth inhibition and a significant increase of the survival time after only one hyperthermia treatment of 30 minutes combined with one intratumoral injection of 1 mM lanthanum. The control animal groups treated by hyperthermia alone or by lanthanum alone don't show any differences of the tumor volume evolution in comparison with untreated animal groups.

Genetic study of a membrane protein: DNA sequence alterations due to 17 lamB point mutations affecting adsorption of phage lambda

Gene lamB encodes the outer membrane receptor for phage lambda in Escherichia coli K12. We have determined the DNA sequence alterations of 17 lamB point mutations which result in resistance to phage lambda h+. The mutations correspond to four phenotypic classes according to the pattern of growth of three phages which use the lambda receptor: lambda h (a one-step host-range derivative of lambda h+), lambda hh* (a two-step host-range derivative of lambda h+) and K10 (another lambdoid phage). Fourteen mutations are of the missense type and correspond to Gly to Asp changes distributed as follows. One class I mutation is at position 382 of the mature lambda receptor. Seven class I* mutations, four of which at least are independent, are at position 401. Six independent class II mutations are at position 151. The three other (class III) mutations are of the nonsense type. They change codons TGG (Trp) into TAG (amber) at positions 120 (two mutations) and 351 (one mutation). Implications of these results for the topological organization of the lambda receptor as well as possible reasons for the limited number of altered sites detected are discussed.

Negative dominance in gene lamB: random assembly of secreted subunits issued from different polysomes

lamB is the structural gene for the lambda receptor, an oligomeric outer membrane protein from Escherichia coli K12 involved in phage lambda adsorption. We show that, under certain conditions, in a strain diploid for gene lamB, all the missense lamB mutations conferring lambda resistance that we have tested are dominant with respect to wild-type. We propose a model which allows a quantitative interpretation of the data. It is based on negative complementation at the level of oligomerisation. Wild-type and mutant subunits would assemble at random forming homo- and hetero-oligomers. Only wild-type homo-oligomers would be efficient for phage inactivation. For some classes of missense mutations the hetero-oligomers would have the capacity to bind, but not to inactivate the phage. The model confirms that active lambda receptor is a trimer and implies that for this secreted protein there is no preferential assembly of subunits originating from the same polysome.

67Ga and 59Fe uptake by tumor cells treated with hyperthermia or hyperthermia plus lanthanum

The uptake of 67Ga-citrate and 59Fe-citrate by tumor cells treated with hyperthermia or with hyperthermia plus lanthanum has been studied. The comparison of these results with ion flux determinations (42K) appears to indicate that hyperthermia alone or combined with lanthanum modifies the ionic permeability of the plasma membrane. This phenomenon seems to be responsible for the increased accumulation of 67Ga and 59Fe.

Ionic competition and 67Ga in vivo accumulation

The effect of several citrates of trivalent cations on 67Ga citrate uptake by tumor-bearing animals has been studied. A relationship between the ionic size of the simultaneously injected cation and the 67Ga uptake inhibition indicates that the cation characteristics (ionic radius and electrical charge) seem to play the most important role in this radioactivity accumulation. The apparent agreement of this phenomenon with the isomorphous replacement hypothesis is discussed.

A system for genetic analysis in gene lamB: first results with lambda-resistant tight mutants

We describe a system for genetic analysis in gene lamb. It consists of a phage which allows mapping, complementation and sequencing studies of lamB mutations and of the sequence of gene lamB. We present results obtained with this system for a set of mutations conferring tight resistant to phage lambda. This leads to a first identification of three residues in the LamB protein which are important for adsorption of phage lambda h+. Residues 151 and 382 are important for reversible adsorption while residues 401 is important for irreversible adsorption. We briefly review other tight mutations affecting gene lamB and discuss some implications of the results on phage receptor interactions, LamB-protein structure and membrane insertion.

[Myocardial scintigraphy using technetium-99m labelled methylene diphosphonate in coronary care units. 82 cases]

Many isotopic methods have been proposed recently for the investigation of normal and diseased myocardium in ischaemic heart disease. The results of myocardial scintigraphy with Technetium 99 m marked methylene diphosphonate in the supine, left lateral and 30 degrees or 45 degrees right anterior oblique incidences are reported. A preliminary study of the tracer's fixation on diseased myocardium was performed in 18 patients. Scintigraphy every 30 minutes over a five hour period showed the optimal time for investigation to be situated between the third and fourth hour after the injection of the tracer. Seventy eight patients were then investigated; 82 scintigraphies were performed, 58 in patients with acute myocardial infarctions confirmed by the usual biological and electrocardiographic changes. A 74% sensitivity and 67% specificity were obtained with the methylene diphosphonate method. These figures varied according to the type of necrosis, subendocardial or transmural and with its extent, chronicity and degree of CPK elevation. Methylene diphosphonate scintigraphy would appear to be less sensitive and more specific for diseased myocardium than other isotopic methods. It may be carried out at the bedside and could improve the diagnosis of acute myocardial infarction when the clinical history and electrocardiographic changes are difficult to interpret.

DNA sequence encoding the NH2-terminal peptide involved in transport of lambda receptor, an Escherichia coli secretory protein

lamB encodes the lambda receptor of Escherichia coli, an outer membrane protein. We have identified the beginning of the lamB gene by correlating DNA nucleotide sequence with a partial sequence of the primary translation product of lamB. We show that lambda receptor is synthesized as a precursor containing an extra 25 amino acids at its NH2 terminus. These amino acids are predominately hydrophobic and probably comprise a structure required for initiation of transport of lambda receptor from the cytoplasm to the outer membrane.

[Neonatal hyperparathyroidism secondary to maternal hypoparathyroidism (author's transl)]

Three cases of neonatal hyperparathyroidism are reported: 2 children born to a mother with idiopathic hypoparathyroidism and a boy born to a mother with pseudohypoparathyroidism. Severe demineralization, decreased plasma calcium levels and very low phosphorus levels were seen in all three cases. The PTH level was high in the two cases in which is was measured. In the second of these, the lack of vitamin D administration since birth led to very severe rickets lesions at the age of 7 weeks. This is an argument for the role of hyperparathyroidism-induced vitamin depletion in the lesions observed and in the maintenance of secondary hyperparathyroidism. Analysis of 10 previously reported cases reveals the severity of the calcium deficiency induced in the fetus in this manner, the frequency of prematurity, of dysmaturity. With calcium and vitamin treatment, biological and radiological findings become normal.

[Ultrasonographic study of the cerebral circulation in elderly subjects (author's transl)]

The amount of diastolic blood flow in the carotid and vertebral axes determines the tolerance capacity of the cerebral circulation to physiological variations. In the elderly subject this "circulatory reserve" is modified by increases in cerebral circulation resistance, but also by various common cardiac or blood pressure disorders. Furthermore, direct visualization of the atheromatous plaques and calcifications in the vessel walls by ultrasonography can reveal lesions that have no clinical expression.

Synthesis and maturation of lambda receptor in Escherichia coli K-12: in vivo and in vitro expression of gene lamB under lac promoter control

The lambda receptor is an outer membrane protein from Escherichia coli K-12 lamB, its structural gene, is part of the maltose regulon. We have cloned this gene in a phage so that it is under the control of the lac promoter. The phage was devised in such a way that it can infect lamB mutants and that chromosomal lamB mutations can be transferred to it. In vivo, the lambda receptor is expressed under lac promoter control and is exported normally to the outer membrane, independently of the expression of the other genes of the maltose regulon. In vitro, DNA of the phage allows efficient synthesis of the lamB product. The protein--or pre-lambda-receptor--made in vitro contains an NH2-terminal sequence of about 25 amino acids not found in the lambda receptor. We have detected no inactivation of phage lambda by the pre-lambda-receptor. Conversion of the pre-lambda-receptor to a form that has the apparent molecular weight of the mature lambda receptor was achieved. A lamB mutation that blocks export in vivo also blocks conversion in vitro.

Bacteriophage lambda-E. coli K12 vector-host system for gene cloning and expression under lactose promoter control: I. DNA fragment insertion at the lacZ EcoRI restriction site

Bacteriophage lambda vectors, derived from lambda plac5 were constructed. Their genomes have only one EcoRI restriction site, located near the end of the beta-galactosidase gene. Recombinants, constructed in vitro, having a DNA fragment inserted in the EcoRI site, are lac- and can be easily recognized. Expression of such foreign genes is then under the control of the lac promoter. Mutations Qam73 and Sam7 greatly increase the amount of beta-galactosidase synthesized by the vector bacteriophage. The lambda ZEQS vector has been certified B2 (EK2) by the French control commission "Recombinaisons génétiques in vitro".

[Construction of derivatives of lambda phage carrying the lamB gene inserted downstream from the promotors of the lactose operon]

The expression of gene lamB, the structural gene for the lambda receptor in E. coli K-12, has been put under the control of the promoter of the lactose operon. This has been done by in vitro recombination using vectors which are derivatives of phage lambda.

malB region in Escherichia coli K-12: specialized transducing bacteriophages and first restriction map

By starting from an Escherichia coli K-12 strain with a lambda phage integrated in the malB region, series of transducing phages carrying part or all of the malB region have been isolated. Genetic mapping of the transduced malB fragments was accomplished by complementation and recombination with known mutations in the region. By using the DNA of these phages, it was found that the malB region is cleaved by the restriction enzymes BglII, EcoRI, HaeII, HincII, SalI, and SstI, but not BamHI, HindIII, KpnI, PstI, XbaI, or XhoI. A physical map was constructed and tentatively correlated with the genetic map.

The radiospirometric flow-volume diagram recording technique and comparative study with conventional spirometry

The spirometric flow-volume diagram recorded for a forced expiration gives information which is used in assessing obstructive or restrictive pulmonary diseases. Regional data of the same kind can be achieved using a simple radiospirometric technique and scintillation camera. A series of images during inspiration and expiration are defined and a time-activity curve with an integration time constant of about 100-200 ms is obtained from the images during the forced expiration phase. The equivalent of the flow-volume diagram, i.e., the time derivative of the activity vs. activity is computed. There were 21 subjects studied in this series. Normal subjects or patients with various diseases underwent classical spirometry, so that the global radioactive diagram could then be compared to the spirometric flow-volume diagram and its parameters expressed in terms of volumes and flow: vital capacity, peak flow, mean flow, flow at mean volume. The correlation with classical spirometry is highly significant. Similarly regional data are consistent with the pulmonary results.

Dynamic cardiac scintigraphy with a multi-imaging device

Cardiac kinetics can be visualized in two ways after i.v. injection of radiopharmaceutics for labeling either the myocardium or the cardiac chambers. The simpler way is the acquisition of the data in analog mode, using a multiimaging device. Thanks to a short time constant for the image advance, the cardiac cycle is divided into 16 frames, the first being triggered by the R wave of the ECG. The data of a large number of synchronized cycles are integrated on a film. This permits an almost continuous way to follow the kinetics of the studied compartments along the cycle. Several views can be registered successively. This procedure yields separately immediate information on the morphology and dynamics of the myocardium, and chambers. To evaluate quantitatively various parameters of left ventricular function a data processor is connected to the gamma camera. Examples of the two types of data are shown and demonstrate that both are useful for appreciating the value of kinetics though they are not yet accurate enough to replace in every case contrast radiologic techniques. Nevertheless, the indications for these procedures are continuously growing, due to technical progresses and the noninvasive nature of the investigation.