Construction and recovery of viable retroviral genomes carrying a bacterial suppressor transfer RNA gene

The integration of retroviral genomes into cellular DNA can induce mutations by altering the expression of nearby cellular genes and can serve to identify the gene affected. The construction of a retrovirus that stably carries a suppressor transfer RNA gene from Escherichia coli has allowed facile recovery of the viral genome in vectors marked with amber mutations. This virus can be used for rapid isolation of cellular sequences at the site of proviral insertion.

Trial of relaxation in reducing coronary risk: four year follow up

On screening 192 men and women aged 35-64 were identified as having two or more of the following risk factors: blood pressure greater than or equal to 140/90 mm Hg, plasma cholesterol concentration greater than or equal to 6.3 mmol/l (243.6 mg/100 ml), and current smoking habit greater than or equal to 10 cigarettes a day. They were randomly allocated to a group for modification of behaviour or to serve as controls. Both groups were given health education leaflets containing advice to stop smoking, to reduce animal fats in the diet, and on the importance of reducing blood pressure. In addition, the treatment group had group sessions of one hour a week for eight weeks in which they were taught breathing exercises, relaxation, and meditation and about managing stress. It had previously been found that after eight weeks and eight months there was a significantly greater reduction in both systolic and diastolic blood pressures in the group taught to relax compared with the control group. After four years of follow up these differences in blood pressure were maintained. Plasma cholesterol concentration and the number of cigarettes smoked were lower in the treatment group at eight weeks and eight months but not at the four year follow up. At four years more subjects in the control group reported having had angina and treatment for hypertension and its complications. Incidence of ischaemic heart disease, fatal myocardial infarction, or electrocardiographic evidence of ischaemia was significantly greater in the control group. If the results of this study could be obtained in a larger study the financial and health care implications would be enormous.

An unusual angiographic appearance of aorto-iliac disease presenting as the Leriche syndrome

An unusual angiographic presentation of Leriche syndrome is described that demonstrates short segment occlusions of iliac arteries with bilaterally symmetrical post-stenotic dilatations.

Reliability of cardiotocography in predicting baby's condition at birth

A prospective study of 6825 labours was undertaken to determine the relation between the Apgar scores of the babies at one minute and the cardiotocograph tracing in labour. The sensitivity of an abnormal tracing was 35.2% for babies who needed intermittent positive pressure ventilation and 20.0% for babies who did not but who had Apgar scores of less than 7. The sensitivity of an abnormal tracing for all babies with an Apgar score of less than 7 was 23.2%. The positive predictive value of an abnormal tracing was 8.7% for babies who needed intermittent positive pressure ventilation and 18.7% for babies who did not but who had an Apgar score of less than 7. The positive predictive value of an abnormal tracing was 27.4% for all babies with an Apgar score of less than 7. The specificity of the tracing was 93.4% for babies with an Apgar score of 7 or over. The relatively high incidence of false positive predictions might be explained on the grounds that abnormalities in the cardiotocograph tracing are a more sensitive indicator of hypoxia than the Apgar score. False negative predictions might have been due to adverse factors other than hypoxia--for example, fetal trauma, compression of the head, infection, and analgesia in labour. These findings suggest that the current overdependence on fetal monitoring by cardiotocography alone should be examined and that other reliable indicators for non-hypoxic fetal distress should be sought.

Epidermoid carcinoma subsequent to a gunshot wound of the face

Reported is a case of epidermoid carcinoma of the face following a gunshot wound. A review of the pertinent literature is included.

Dermal grafts to bony defects in irradiated and nonirradiated tissues

Coverage of intraoral ablative defects presents many different problems. Free dermal grafts have been used to cover exposed mandibular bone in dogs. Grafts were placed in animals both before and after irradiation. Grafts were uniformly successful in animals not previously irradiated but failed when placed after irradiation.

A novel phenazine antifungal antibiotic, 1,6-dihydroxy-2-chlorophenazine. Fermentation, isolation, structure and biological properties

A novel, solvent extractable, antibiotic complex has been purified from the fermentation broth of an unusual member of the genus Streptosporangium. Two of the major components were isolated from the complex by alumina column chromatography. One of the components was identified as a previously reported compound, 1,6-dihydroxyphenazine. The other component was a novel chlorine containing phenazine, 1,6-dihydroxy-2-chlorophenazine, which exhibited broad spectrum antifungal activity in vitro against dermatophytes and Candida.

Type 2 (non-insulin-dependent) diabetes mellitus and HLA antigens in Papua New Guinea

HLA phenotypes were studied in 57 Type 2 (non-insulin-dependent) diabetic Papuan patients and the results compared with control subjects of the same Austronesian origin. An association was found between disease and BW62, a split antigen of B15, with corrected probability significant at the 5% level. The frequencies of B13 and BW22 were also increased in diabetic patients but the differences were not statistically significant. Although it has been postulated that Melanesian communities have protection against diabetes, they have a high frequency of BW62, which would imply, from the association found in this study, that susceptibility to Type 2 diabetes has yet to become manifest in them.

Partial purification and properties of rat liver glutaminase

The mitochondrial enzyme phosphate-dependent glutaminase was partially purified from rat liver. The enzyme had Mr 290 000 as judged by chromatography on Sephacryl S-300. After sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of the preparation, glutaminase was tentatively identified with a peptide of Mr 73 500. The concentration-dependence on glutamine was highly sigmoidal, with half-maximum velocity at 22 mM-glutamine. Half-maximum activity was obtained with 5 mM-phosphate. The enzyme required ammonia as an obligatory activator, in agreement with previous reports on intact and sonicated mitochondria. These findings further differentiate liver glutaminase from the phosphate-dependent glutaminase present in kidney and several other tissues.

Extremely high levels of natural killer cells in angioimmunoblastic lymphadenopathy

Analysis of peripheral blood leukocytes from a patient with angioimmunoblastic lymphadenopathy using monoclonal antibodies and the fluorescence-activated cell sorter showed an unusually high proportion of cells that were OKT10+OKM1+63D3-. Since a large proportion of the large granular lymphocytes associated with natural killing in humans bears this surface phenotype, both blood and lymph node cells were subsequently tested for cell-mediated cytotoxicity in natural killer (NK)-cell assays. Following chemotherapy, both cells bearing the NK surface phenotype and the NK cytotoxicity disappeared and a population of cells, bearing none of the typical lymphocyte or monocyte markers, became dominant. At this point the patient was diagnosed as having immunoblastic sarcoma and shortly thereafter succumbed to his disease. In the few cases where extremely high levels of NK activity have been reported, the tumor cells themselves have been responsible for cell-mediated cytotoxicity. In this case, the final tumor population had no NK activity. Thus either a subpopulation of cytotoxic tumor cells was destroyed by chemotherapy or the patient had expanded numbers of NK cells reacting against his tumor prior to therapy.

The hazimicins, a new class of antibiotics. Taxonomy, fermentation, isolation, characterization and biological properties

The hazimicins, a new class of broad spectrum antibiotics with at least 2 active components (5 and 6), were isolated from the fermentation of Micromonospora echinospora var challisensis SCC 1411. The complex was separated from the broth by a solvent extraction procedure, and the individual components were separated by column chromatography. The two primary active components are isomers, with unique structures shown to be di-tyrosine analogs containing two isonitrile groups. The antibiotic has in vitro activity against Gram-positive and Gram-negative bacteria, and in vitro activity against yeasts and dermatophytes.

Use of x-ray microanalysis to monitor diffusion of Zn from a cement into human dentin

Energy dispersive x-ray spectrometry (EDAX system), with scanning electron microscopy was used to detect diffusion of Zn from a source in human dentin and the system was tested for sensitivity and reproducibility. Sections of human teeth in which a ZnO-eugenol cement had been placed in a cavity in the dentin in vivo were prepared and x-ray microanalytical measurements carried out. We found that values of counts for Zn, Ca and P in the same field were linear up to a total counting time of 60 sec. We further found that reproducibility of values between repeat examinations of the same specimens on different days was excellent. The concentration of Zn in the dentin decreased exponentially with distance from source within the distance tested. We conclude that the system can be used to detect trace concentrations of Zn, and that accordingly the diffusion behavior of a variety of ions in dentin could be monitored.

Dislocation of the carpometacarpal joint of the thumb. A report of four cases

In four cases of complete carpometacarpal dislocation of the thumb, closed reduction, although easily performed, usually had unstable results. Open reduction and internal fixation with Kirschner wires were used in two cases. The third case was stable after open reduction. The fourth patient was treated by closed reduction and percutaneous Kirschner wire fixation. The joints were immobilized in spica casts for six weeks. At follow-up examinations, two patients had asymptomatic dorsal subluxation. At two years' follow-up examinations, two of the four patients had dorsal subluxations. Open reduction and internal fixation alone were not adequate for this type of injury. The dorsal capsule and ligament should be explored during surgery and reconstructed by free tendon grafts.

Acetyl glyceryl ether phosphorylcholine-stimulated human platelets cause pulmonary hypertension and edema in isolated rabbit lungs. Role of thromboxane A2

Macrophages, neutrophils, and platelets may play a role in acute edematous lung injury, such as that seen in the adult respiratory distress syndrome (ARDS), but their potential actions and interactions are unclear. Because stimulated human macrophages and neutrophils can release acetyl glyceryl ether phosphorylcholine (AGEPC), a potent platelet activator, we hypothesized that in ARDS, leukocyte release of AGEPC might stimulate platelets to release thromboxane A2 (TXA2), which then produces pulmonary hypertension and lung edema. In support of this premise, we found that pulmonary hypertension and edema occurred in isolated rabbit lungs perfused with human platelets and AGEPC, but not with platelets or AGEPC alone. Infusion of a vasodilator (nitroglycerin) to maintain base-line pulmonary artery pressures in lungs perfused with platelets and AGEPC prevented the development of lung edema suggesting that platelet and AGEPC-induced edema was hydrostatic in nature. Additional experiments suggested that the increased pressure was a result of TXA2 release from platelets stimulated by AGEPC. Specifically, preincubation of platelets with imidazole, a thromboxane synthetase blocker, prior to infusion with AGEPC significantly diminished pulmonary hypertension and prevented lung edema. Furthermore, pretreating lung preparations with 13-azaprostanoic acid, a TXA2 antagonist, before infusion of AGEPC and untreated platelets also reduced the pulmonary hypertension and blocked the lung edema. The role of TXA2 was further suggested when perfusates from lungs infused with platelets and AGEPC developed high levels of TXA2, whereas perfusates from controls did not. These results suggest that platelet aggregation induced by AGEPC may contribute to ARDS by releasing TXA2, which raises microvascular pressure and increases edema formation, especially when an underlying permeability defect is present.

The role of T, B and adherent cells in the in vitro immune response of TEPC-183-bearing mice

In order to analyse the mechanism of immunosuppression of plasmacytoma-bearing mice, the role of enriched T cells, B cells, and adherent cells from the spleens of normal and TEPC-183 plasmacytoma (IgM,k) bearing mice in the primary in vitro immune response was investigated. Nylon-wool-enriched fractions of T and B cells were used in the study of T-cell-dependent immune responses to the 2-4-6-trinitrophenyl ligand. When 5 × 10^-5M 2-mercaptoethanol (2-ME) was present in cultures, TEPC-183 spleen cells or their T- or B-cell-enriched fractions did not suppress the immune responses of normal spleen cells. However, in the absence of 2-ME, T- or B-cell fractions were as effective as unfractionated TEPC-183 spleen cells in causing suppression of normal immune responses.

T and B cells derived from TEPC-183 spleens gave minimal anti-trinitrophenyl specific plaque-forming-cell responses when co-cultured with adherent cells from either normal or TEPC-183 spleens. In contrast, either T- or B-cell fractions from TEPC-183 spleens were at least partially competent when co-cultured with B or T cells from normal spleens. The data thus suggest that the suppressed state of TEPC-183 spleen cells may be due to defective T—B cell interaction. It was consistently observed that splenic adherent cells from TEPC-183-bearing mice were neither suppressed nor suppressive for the in vitro immune responses of normal splenic lymphocytes at the ratios tested. Adherent peritoneal exudate (PE) cells from either normal or TEPC-183-bearing mice were equally suppressive for the in vitro immune responses of normal splenic lymphocytes at the PE cell to lymphocyte ratios of 1:10 and 1:35. Thus, the suppressive characteristic of adherent PE cells in this system is not specific for TEPC-183 plasmacytoma in mice.

TEPC-183 spleens were found to contain 35% or more esterase-positive cells, compared with approximately 5% esterase-positive cells present in normal spleens. The possible role of esterase-positive cells, T cells, B cells, and adherent cells in the observed suppression will be discussed.

Computation of ammonium bisulfate aerosol deposition in conducting airways

Experimental measurements of the growth of monodisperse dry NH4HSO4 aerosols by H2O vapor condensation have been reported in the literature. These data are incorporated into an aerosol deposition model to study the behavior of inhaled NH4HSO4 particles, which is of concern in relation to human health. The tracheobronchial tree is described by Weibel's model A morphology, and Landahl's formulas are used to compute particle deposition efficiencies. Enhanced losses in the trachea due to the action of the laryngeal jet are accounted for by using an empirical deposition efficiency equation. The effect of NH4HSO4 aerosol growth is quantitated by comparisons of total and intrabronchial deposition probabilities with those of a nonhygroscopic aerosol of equal aerodynamic size. Computations indicate that hygroscopic growth effects are a function of the size of the particles inhaled. Total deposition efficiencies of NH4HSO4-H2O droplet aerosols are greater than those of nonhygroscopic aerosols only if the former originate from dry NH4HSO4 particles exceeding a critical geometric diamter of 0.3 micrometer. Growth effects are explained in terms of the relative efficiencies of the dominant deposition mechanisms active in the lung.

Modelling determinants of health

The linear regression procedure of stepwise elimination has been used to examine the association between a range of environmental variables and infant mortality rates (IMR) in Sri Lanka. The nature of the water supply was found to be significantly associated with IMR. Latrines were significantly associated with IMR once qualitative differences between districts were allowed for. Other 'environmental determinants of health', 3 indices of housing quality and the presence of electricity supplies, were not significant. The cost of effecting changes in IMR by extending subsidies to water supply improvements is estimated.

Modeling the dose distribution of H2SO4 aerosols in the human tracheobronchial tree

The influence of hygroscopic growth within the human respiratory tract upon the deposition of H2SO4 aerosols is investigated using an analytical model. Particles are assumed to reach their equilibrium size and density upon entering the trachea from either the nasal or oral pharyngeal compartments. Calculated data are used to describe the equilibrium values for specified relative humidity conditions which simulate the atmosphere, inhalation exposure chambers, and the lung. Theoretical equations are used to calculate aerosol deposition efficiencies within conducting airways of the tracheobronchial tree. Hygroscopic growth is shown to affect both the total dose deposited and its regional distribution. For an inspiratory flow rate of 30 L min-1, the total deposition efficiency of H2SO4-and-H2O droplets, resulting from water condensation upon H2SO4 particles of initial geometric diameter D0, is greater than inspired nonhygroscopic particles of identical aerodynamic diameter when D0 greater than 0.1 mu m. The opposite is found when D0 less than 0.1 mu m. The effects of hygroscopic growth are explained in terms of the changing deposition efficiencies of the inertial impaction, sedimentation and diffusion mechanisms. Results imply that it is important that hygroscopic growth within the human respiratory tract be accounted for when assessing the potential health hazard of airborne particulate matter.

The incidence of selected vaginal infections among pregnant urban blacks

A total of 232 Black antenatal patients was assessed in a cross-sectional study and a total of 80 in a longitudinal study. Trichomonas vaginalis infection occurred almost twice as frequently as Candida albicans infection. Neisseria gonorrhoeae infection was present in 10% of patients, and mixed infections were present in 34% of patients.

Rhinorrhea associated with intracranial cholesteatomas and an "empty sella."

Three related disorders in the same patient, namely bilateral primary intracranial cholesteatomas, an "empty sella" syndrome, and a cerebrospinal rhinorrhea are reported. No previous report of bilateral symmetrical cholesteatomas has been made, though single intracranial cholesteatomas have frequently been recorded in medical literature. The "empty sella" syndrome is generally considered to be from a herniation of the subarachnoid into the sella through a deficient diaphragma sella, and was first defined by Ommaya in 1968. Non-traumatic (spontaneous) rhinorrhea remains an uncommon disease initially described in 1826. Experience of the individual otolaryngologist is limited in this region because of infrequent occurrence and because definitive treatment is directed to other specialties. On the other hand, the ear, nose and throat physician may be the first to interpret a drainage from the nose. With this in mind, the etiologic, clinical and management factors in the present case are discussed.

Effects of the health service and environmental factors on infant mortality: the case of Sri Lanka

One of the findings of this study is that regional variations in the infant mortality rates of Sri Lanka are large, ranging from 26 per 1000 live births in Jaffna to 91 per 1000 in Nuwara Eliya, a tea estate district. These differences are more strongly associated with regional variations in environmental determinants of mortality than with regional variations in public health expenditure. The most significant environmental factor associated with interregional infant mortality rates was to be the nature of the water supply (r = -0.82, significant at the 99% level). Regional government expenditure on health had only a weak association with infant mortality rates (r = 0.08).

Hydroheptin: a water-soluble polyene macrolide. II. Chemical and biological properties

Hydroheptin, a new polyene macrolide antifungal antibiotic, is co-produced with the antibiotic, chartreusin, by a strain of Streptomyces chartreusis designated as IMRU 3962 isolated in our laboratory. The unique water-solubility of this antibiotic at neutrality, revealing in aqueous solution molecular dispersion and an ultraviolet-visible absorption spectrum characteristic of an all-trans heptaene chromophore, clearly distinguishes it from all previously-described and naturally-occurring heptaene macrolides. The isolation and identification of the amino sugar, mycosamine (3-amino-3,6-dideoxy-D-mannose), in acid hydrolysates of hydroheptin and the absence of an aromatic amine upon retrograde alkaline dealdolization of the molecule certainly characterize the antibiotic as a member of the non-aromatic heptaene macrolide group. Chromatographic and countercurrent distribution studies likewise support its novelty. With little or no demonstrable activity against bacteria, hydroheptin as compared to other non-aromatic heptaene macrolides exhibits excellent but somewhat less activity against a wide variety of yeasts and fungi. Likewise, its parenteral toxicity appears to be less than that of other heptaene macrolides.

Biosynthetic pathway leading to gentamicin C2b

Incubation of Micromonospora purpurea SC 1210 (NRRL 5467) with L-[methyl-14C]methionine yielded [methyl-14C]gentamicin A and methyl-14C-labeled antibiotic JI-20A in a molar radioactivity ratio of 9:2. We did not isolate methyl-14C-labeled gentamicin X2, which was expected as an intermediate based on the biosynthetic pathways proposed by others. Addition of methyl-14C-labeled antibiotic JI-20A to M. purpurea SC 1124 (NRRL 8102) yielded [methyl-14C]-gentamicin C1a and [methyl-14C]gentamicin C2b in variable molar radioactivity ratios. These data do not support the biosynthetic pathway leading to gentamicin C2b proposed by Testa and Tilley.

Conduction disturbances in patients with calcified mitral annulus diagnosed by echocardiography

Clinical, radiologic and histo-pathological observations have suggested that conduction disturbances (CD) are frequent in patients with calcified mitral annulus (CMA). To determine the incidence of CD, 65 consecutive patients with CMA were studied. Sixty-five normal individuals, matched for age and sex served as a control group. CMA has been identified by M-mode echocardiography, cross-sectional echo and image amplifier fluoroscopy. CD were present in 23 patients with CMA as compared to seven patients in the control group (p less than 0.01). Three patients developed complete atrioventricular block (4.6%) during hospitalization requiring artificial pacemakers. We conclude that, 1) early detection of CMA in the elderly is useful in predicting a higher incidence of CD. 2) Complete heart block is more frequent in patients with CMA. 3) Frequent ECG follow-up in these patients has proven to be useful in avoiding serious clinical complications.

Method for qualitative determination of 2-deoxystreptamine

We have developed a qualitative method to assay for the presence of 2-deoxystreptamine in hydrolysates of crude aminoglycoside preparations using a 2-deoxystreptamine-requiring idiotrophic mutant. The assay involves (i) incubation of a 2-deoxystreptamine-requiring mutant with 1 mg of a hydrolyzed preparation from a crude unknown antibiotic mixture per ml, and (ii) examination of the resultant incubation mixture for production of antibiotic(s) by disk assay.

Gallium-68 labeled red cells and platelets: new agents for positron tomography

Red cells and platelets are labeled with Ga-68 by preparing the tga-68-hydroxy-quinoline (oxide) complex and mixing the complex with the separated cellular components. The complex is prepared by first breaking the Ga-68 EDTA chelate with concentrated hydrochloric acid, adsorption of the galluim on a strong anionic ion-exchange column, and elution of the gallium activity with distilled water. Oxine is added, the oxine complex extracted into chloroform, and--following evaporation and dissolution--the solution is added to either red cells or platelets that have been centrifuged from whole blood, washed, and suspended in normal saline. After 15 min of incubation , labeling efficiencies of greater than 90% and yields of 7 mCi are obtained from 18 mCi of Ga-68 EDTA eluted from the generator. After injection of the gallium-labeled red cells in dogs, excellent blood pool images were obtained by positron tomography. The distribution corresponded to that of 11CO-labeled red cells. When labeled platelets were injected into dogs with experimentally induced intimal injury of on carotid artery, the area of injury was clearly visualized 40 min after tracer injection.

Human splanchnic metabolism during diabetic ketoacidosis

Splanchnic exchange rates of glucose, acetoacetate, beta-hydroxybutyrate, lactate, pyruvate, glycerol, alanine, glutamine, glutamate, free fatty acids, and triglycerides were measured in eight patients during moderate to severe diabetic ketoacidosis. Their arterial glucose concentration was 20.68 (9.80-52.79) mumole/liter and tic glucose release was 0.77 (0.09-2.44) mmole/min. Gluconeogenesis accounted for about one-half of net splanchnic glucose release, assuming quantitative conversion of net splanchnic extracted lactate, pyruvate, glycerol, alanine, and alpha-ketoglutarate equivalents to glucose. Net splanchnic free fatty acid extraction was 0.24 (0.09-0.52) mmole/min. There was a positive correlation between free fatty acid uptake and ketone-body release. Net splanchnic acetoacetate release was 0.50 (0.05-0.92) mmole/min and beta-hydroxybutyrate release was 0.35 (-0.16 to 0.84) mmole/min. Total ketone-body release was 0.84 (0.37-1.61) mmole/min. The wide ranges of net splanchnic glucose and ketone-body production rates show the heterogeneous characteristics of the diabetic patient in ketoacidosis. It is concluded that the hyperglycemia and hyperketonemia of diabetic ketoacidosis is due to the lack of reciprocity among rates of hepatic glycogenlysis, gluconeogenesis, and ketogenesis resulting in inappropriate net splanchnic release of glucose and ketone bodies.

A new actinomycin complex produced by a Micromonospora species: fermentation, isolation, and characterization

A species of Micromonospora, Micromonospora floridensis NRRL 8020, has been found to produce an actinomycin complex consisting of at least 25 active components. After solvent extraction of the complex, separation of the individual components was carried out by preparative thin-layer chromatography. Hydrolysis and subsequent electrophoretic and chromatographic identification of the amino acid content of each of the isolated components have shown differences from known actinomycins, and the probability exists that these contain a number of amino or imino acids not previously found in other members of this group of antibiotics.

Effects of prophylactic antibiotics on colonic healing

The effect of antibiotic colon preparation on the tensile strength and morphologic appearance of colonic anastomoses has been investigated in dogs. Preparation with preoperative kanamycin did offer a slight benefit over mechanical bowel cleansing. The addition of erythromycin and kanamycin to the preoperative bowel preparation significantly (p less than 0.001) improved the mean tensile strengh of the healing colonic anastomosis. Continuation of erythromycin and kanamycin for one week postoperatively almost doubled the mean tensile strength of the healing anastomosis. Continuation of erythromycin without kanamycin in the postoperative period provided little protection over the preoperative administration of kanamycin and erythromycin. Histologic examination showed that erythromycin and kanamycin given during the pre- and postoperative period changed the mode of healing from that of secondary intention to healing by first intention. The findings support the concept that soilage of the peritoneal cavity at the time of elective colon surgery is not as important as leakage caused by poor anastomotic healing. Antibiotic bowel preparation with kanamycin and erythromycin improves the healing of colonic anastomoses.