Angiopoietins 3 and 4: diverging gene counterparts in mice and humans

The angiopoietins have recently joined the members of the vascular endothelial growth factor family as the only known growth factors largely specific for vascular endothelium. The angiopoietins include a naturally occurring agonist, angiopoietin-1, as well as a naturally occurring antagonist, angiopoietin-2, both of which act by means of the Tie2 receptor. We now report our attempts to use homology-based cloning approaches to identify new members of the angiopoietin family. These efforts have led to the identification of two new angiopoietins, angiopoietin-3 in mouse and angiopoietin-4 in human; we have also identified several more distantly related sequences that do not seem to be true angiopoietins, in that they do not bind to the Tie receptors. Although angiopoietin-3 and angiopoietin-4 are strikingly more structurally diverged from each other than are the mouse and human versions of angiopoietin-1 and angiopoietin-2, they appear to represent the mouse and human counterparts of the same gene locus, as revealed in our chromosomal localization studies of all of the angiopoietins in mouse and human. The structural divergence of angiopoietin-3 and angiopoietin-4 appears to underlie diverging functions of these counterparts. Angiopoietin-3 and angiopoietin-4 have very different distributions in their respective species, and angiopoietin-3 appears to act as an antagonist, whereas angiopoietin-4 appears to function as an agonist.

Direct evidence that leukemic cells present HLA-associated immunogenic peptides derived from the BCR-ABL b3a2 fusion protein

The BCR-ABL oncogene is central in the pathogenesis of chronic myeloid leukemia (CML). Here, tandem nanospray mass spectrometry was used to demonstrate cell surface HLA-associated expression of the BCR-ABL peptide KQSSKALQR on class I-negative CML cells transfected with HLA-A*0301, and on primary CML cells from HLA-A3-positive patients. These patients mounted a cytotoxic T-lymphocyte response to KQSSKALQR that also killed autologous CML cells, and tetramer staining demonstrated the presence of circulating KQSSKALQR-specific T cells. The findings are the first demonstration that CML cells express HLA-associated leukemia-specific immunogenic peptides and provide a sound basis for immunization studies against BCR-ABL.

Ror2, encoding a receptor-like tyrosine kinase, is required for cartilage and growth plate development

Receptor tyrosine kinases often have critical roles in particular cell lineages by initiating signalling cascades in those lineages. Examples include the neural-specific TRK receptors, the VEGF and angiopoietin endothelial-specific receptors, and the muscle-specific MUSK receptor. Many lineage-restricted receptor tyrosine kinases were initially identified as 'orphans' homologous to known receptors, and only subsequently used to identify their unknown growth factors. Some receptor-tyrosine-kinase-like orphans still lack identified ligands as well as biological roles. Here we characterize one such orphan, encoded by Ror2 (ref. 12). We report that disruption of mouse Ror2 leads to profound skeletal abnormalities, with essentially all endochondrally derived bones foreshortened or misshapen, albeit to differing degrees. Further, we find that Ror2 is selectively expressed in the chondrocytes of all developing cartilage anlagen, where it essential during initial growth and patterning, as well as subsequently in the proliferating chondrocytes of mature growth plates, where it is required for normal expansion. Thus, Ror2 encodes a receptor-like tyrosine kinase that is selectively expressed in, and particularly important for, the chondrocyte lineage.

Phenotypic comparison of periodontal ligament cells in vivo and in vitro

The mammalian periodontal ligament contains heterogeneous populations of connective tissue cells, the precise function of which is poorly understood. Despite close proximity to bone and the application of high amplitude physical forces, cells in the periodontal ligament (PL) are capable of expressing regulatory factors that maintain PL width during adult life. The study of PL homeostasis and PL cell differentiation requires culture and phenotypic methods for precise characterization of PL cell populations, in particular those cells with an inherently osteogenic program. Currently it is unknown if cells cultured from the PL are phenotypically similar to the parental cells that are present in the tissues. We have compared the phenotype of cells in vivo with cells derived from the PL and expanded in vitro to assess the general validity of in vitro models for the study of phenotypic regulation in vivo. Rat PL cells were isolated by either scraping the root of the extracted first mandibular molars (Group A), or by scraping the alveolar socket following extraction of first mandibular molars (Group B), or by obtaining a mixture of cells after disaggregating a block of tissue consisting of first mandibular molar, PL and the surrounding alveolar bone (Group C). Cultured cells at confluence were fixed and immunostained for alpha-smooth muscle actin (alpha-SMA), osteopontin (OPN), alkaline phosphatase (AP), or bone sialoprotein (BSP). For in vivo assessments, frontal sections of rat first mandibular molar were immunostained for alpha-SMA, OPN, AP and BSP. We examined osteogenic differentiation of cultured PL cell cultures by bone nodule-forming assays. In vivo and at all examined sites, > 68% of PL cells were immunostained for AP; approximately 50% and approximately 51% for OPN and alpha-SMA (p = 0.3), respectively, while only approximately 8% were positively stained for BSP (p < 0.01). Analysis of cultured PL cells in Groups A, B and C showed 54%, 53%, and 56% positive staining for alpha-SMA respectively; 51%, 56%, 54% for OPN; 66%, 70%, 69% for AP and 2.2%, 1.4% and 2.8% for BSP. The mean percentage of PL cells in situ stained for the different markers was similar to that of cultured PL cells (Group A approximately Group B approximately Group C in situ for p > 0.2) except for BSP which was 3 to 4 fold higher in vitro (p < 0.01). PL cell cultures treated with dexamethasone showed mineralized tissue formation for all groups (A, B, C), but no mineralized tissue formation was detected in the absence of dexamethasone. As PL cells express quantitatively similar phenotypes in vitro and in vivo, we conclude that the in vitro models used here for assessment of PL cell differentiation appear to be appropriate and are independent of the cell sampling method. Further, dexamethasone-dependent progenitors are present both on the root and bone-related sides of the PL.

Prevalence of Barrett's esophagus by endoscopy and histologic studies: a prospective evaluation of 306 control subjects and 376 patients with symptoms of gastroesophageal reflux

The classic endoscopic diagnosis of a Barrett's esophagus (BE) is based on the finding of > or =3 cm, of distal esophagus covered by specialized columnar epithelium. However, currently, it is based on the finding of intestinal metaplasia (IM) at the squamous-columnar mucosal junction, independent of its extent. The aim of this study was to determine the prevalence of Barrett's esophagus by endoscopic and histological findings in control subjects and in patients with symptoms of gastroesophageal reflux (GER). Three hundred and six control subjects and 376 patients with symptoms of gastroesophageal reflux were included in this prospective study. Patients with Barrett's esophagus were classified in three groups as follows. 1. Intestinal metaplasia at the cardia. When endoscopy showed non-Barrett's esophagus, but histological intestinal metaplasia was found. 2. Short-segment Barrett's esophagus. When <3 cm, was covered with tongues or finger-like or creeping substitution of distal esophagus. 3. Long-segment Barrett's esophagus. When > 3 cm, of distal esophagus was covered by specialized columnar epithelium. Two biopsies at the antrum, four biopsies at the squamous-columnar junction and one or two at the distal esophagus were taken. In control subjects, 1.6% showed histological IM at the esophagogastric junction. In patients with GER without esophagitis or with erosive esophagitis, IM was found in 18% and 10.7% respectively. 'Short-segment' Barrett's esophagus was three times more frequent than 'long-segment' Barrett's esophagus. Patients with Barrett's esophagus were significantly older than the other groups. The presence of complications or erosions, peptic ulcer or stricture were significantly more frequent among patients with 'long-segment' Barrett's esophagus (p < 0.0001). The prevalence of dysplasia was similar in all groups of patients with Barrett's esophagus. Complications such as ulcers, stricture and dysplasia were exclusively seen among patients with BE, whereas non-Barrett's patients did not exhibit these complications. In control subjects, IM can be found in a low percentage of cases. Among patients with symptoms of GER, the classic endoscopic diagnosis of a Barrett's esophagus can underestimate this condition in 80% of the cases. Patients with intestinal metaplasia at the cardia already present 17% of the cases with low-grade dysplasia. In all patients with symptoms of GER, systematic biopsies at the squamous-columnar junction should be taken.

Late follow-up of polypoid lesions of the gallbladder smaller than 10 mm

OBJECTIVE

To determine the variation in number, size, and symptoms in patients with polypoid lesions of the gallbladder.

SUMMARY BACKGROUND DATA

A polypoid lesion is any elevated lesion of the gallbladder mucosa. Several studies have been reported in patients undergoing cholecystectomy, but little information exits regarding the natural history of these lesions in nonoperated patients.

METHODS

A total of 111 patients with ultrasound diagnosis of polypoid lesions smaller than 10 mm were followed up by clinical evaluation and ultrasonography. Twenty-seven patients underwent cholecystectomy.

RESULTS

There was no difference in terms of gender. Nearly 80% of the lesions were smaller than 5 mm; they were single in 74%. In nonoperated patients, 50% remained of similar size at the late follow-up, 26.5% increased in number and size, and 23.5% shrank or disappeared. Among the operated patients, 70% corresponded to cholesterol polyps. None of the patients developed symptoms of biliary disease or gallstones or adenocarcinoma.

CONCLUSIONS

Ultrasound is useful in the follow-up of patients with polypoid lesions of the gallbladder. Lesions smaller than 10 mm do not progress to malignancy or to development of stones, and none produced symptoms or complications of biliary disease.

Prevalence of intestinal metaplasia according to the length of the specialized columnar epithelium lining the distal esophagus in patients with gastroesophageal reflux

The diagnosis of Barrett's esophagus is based on the presence of intestinal metaplasia (IM) at the distal esophagus. The aim of this study was to determine the prevalence of IM in patients with symptoms of gastroesophageal reflux in whom endoscopically a segment of distal esophagus was covered by columnar epithelium (CE). In a prospective, descriptive and transversal study, 492 patients (33%) from 1480 patients with gastroesophageal reflux, in whom endoscopic evaluation demonstrated the presence of a short-segment CE measuring less than 3 cm or a long-segment CE measuring more than 3 cm, were evaluated. From each patient, several biopsy specimens were taken, which were stained with hematoxylin-eosin and Alcian blue pH 2.5. Out of 492 cases, 421 patients (86%) presented with a short-segment CE and 71 patients (14%) had a long-segment CE. Among these 71 cases, 38 had a 3-6 cm-length CE, 21 patients had a 6.1-10 cm-length CE and 12 patients had CE more than 10.1 cm in length. Endoscopic short-segment CE was six times more frequent than long-segment CE. The prevalence of IM was 35% among patients with short-segment CE and increased progressively according to the length of CE, being 100% in patients with > 10 cm in length. Therefore, true short-segment BE was three times more frequent during endoscopic studies than long-segment BE. Dysplasia in the metaplastic epithelium also increased parallel to the length of the CE. True BE (presence of IM at the columnar epithelium lining the distal esophagus), was present in 13.6% of all patients with symptoms of gastroesophageal reflux submitted to endoscopic evaluation. Short-segment BE is three times more frequent than long-segment BE, and endoscopic and bioptic evaluation is fundamental in all cases with gastroesophageal reflux who exhibit some segment of the distal esophagus lined by columnar epithelium, even if it is > or = 1 cm long.

Late results of a randomized clinical trial comparing total fundoplication versus calibration of the cardia with posterior gastropexy

BACKGROUND

The aim was to perform a prospective randomized study in patients with chronic gastro-oesophageal reflux treated either by total fundoplication or calibration of the cardia with posterior gastropexy. Late follow-up considered subjective and objective parameters, and related outcome to the presence of Barrett's oesophagus.

METHODS

A total of 164 patients were randomized to fundoplication (n = 76) or calibration of the cardia (n = 88). They were evaluated by clinical questionnaire, upper gastrointestinal endoscopy with biopsies, oesophageal manometry and gastro-oesophageal reflux studies, including scintigraphy and 24-h oesophageal pH monitoring.

RESULTS

There were no operative deaths. There was 95 per cent follow-up at a mean of 85 months. The mean recurrence rate for both operations was near 40 per cent at 10 years, but patients without Barrett's oesophagus had a recurrence rate after both operations of around 23 per cent compared with 83 per cent after 10 years for those with Barrett's oesophagus (P < 0.0001). Low-grade dysplasia developed in 13 per cent of the patients with Barrett's oesophagus. There were significant differences in all objective parameters in a comparison of patients with Visick I or II and those with Visick III or IV disease at the late assessment.

CONCLUSION

Both total fundoplication and calibration of the cardia with posterior gastropexy had similar subjective and objective late results. However, results were significantly worse in patients with Barrett's oesophagus.

Molecular and cytological characterization of ribosomal RNA genes in Chenopodium quinoa and Chenopodium berlandieri

The nucleolus organizer region (NOR) and 5S ribosomal RNA (rRNA) genes are valuable as chromosome landmarks and in evolutionary studies. The NOR intergenic spacers (IGS) and 5S rRNA nontranscribed spacers (NTS) were PCR-amplified and sequenced from 5 cultivars of the Andean grain crop quinoa (Chenopodium quinoa Willd., 2n = 4x = 36) and a related wild ancestor (C. berlandieri Moq. subsp. zschackei (Murr) A. Zobel, 2n = 4x = 36). Length heterogeneity observed in the IGS resulted from copy number difference in subrepeat elements, small re arrangements, and species-specific indels, though the general sequence composition of the 2 species was highly similar. Fifteen of the 41 sequence polymorphisms identified among the C. quinoa lines were synapomorphic and clearly differentiated the highland and lowland ecotypes. Analysis of the NTS sequences revealed 2 basic NTS sequence classes that likely originated from the 2 allopolyploid subgenomes of C. quinoa. Fluorescence in situ hybridization (FISH) analysis showed that C. quinoa possesses an interstitial and a terminal pair of 5S rRNA loci and only 1 pair of NOR, suggesting a reduction in the number of rRNA loci during the evolution of this species. C. berlandieri exhibited variation in both NOR and 5S rRNA loci without changes in ploidy.

'Carditis': an objective histological marker for pathologic gastroesophageal reflux disease

In a prospective endoscopic and bioptic study, 141 control subjects and 359 patients with symptoms of gastroesophageal reflux (GER) were included to determine the prevalence of cardial epithelium inflammation or 'carditis' and to determine the prevalence of Helicobacter pylori in this area. Two biopsies at the antrum, four distal to the squamous-columnar junction and two proximal in the esophageal mucosa, were taken. Patients with gastroesophageal reflux were divided into four groups, according to the severity of endoscopic findings: patients without esophagitis, patients with erosive esophagitis, patients with short-segment and long-segment Barrett's esophagus (BE). Control subjects had normal histological findings at the cardia in 90% of cases, fundic mucosa being present twice as cardial epithelium. Carditis was present in 8% of cases and intestinal metaplasia (IM) in 2%. On the contrary, patients with GER had carditis in nearly 50% of cases. Intestinal metaplasia was present in 12% of cases with GER without esophagitis or erosive esophagitis, in 35% of cases with short-segment BE and in 65% of the cases with long-segment BE. IM at the antrum was present in only 5% of cases. Helicobacter pylori at the squamous-columnar junction was present in 13% of control subjects and in 30% of the patients with GER. It is concluded that carditis is an easy and objective marker for the presence of chronic gastroesophageal reflux and the presence of Helicobacter pylori at this region must be carefully evaluated in order to determine some pathogenic role for the development of Barrett's esophagus.

Changing the pH of the external aqueous phase may modulate protein entrapment and delivery from poly(lactide-co-glycolide) microspheres prepared by a w/o/w solvent evaporation method

The milk model protein, beta lactoglobulin (BLG), was encapsulated into microspheres prepared by a multiple emulsion/solvent evaporation method. The effect of the pH of the outer aqueous phase on protein encapsulation and release as well as on microsphere morphology has been investigated. At all tested pH values, the encapsulation efficiency was shown to decrease with increasing the initial amount of BLG. This was correlated with the reduced stability of the primary emulsion as the initial BLG increased. In addition, reducing the solubility of BLG in the external aqueous phase by decreasing the pH to the isoelectric point of BLG (pI 5.2) resulted in an improved protein encapsulation. Moreover, it was shown that combining pH modification and optimal stability of the first emulsion yielded microspheres with a high encapsulation efficiency. However, release kinetic studies revealed that a significant burst release was observed with microspheres loaded with large amounts of BLG, especially when prepared in a medium at pH 5.2. This burst effect was attributed to morphology changes in the microsphere surface which was characterized by the presence of pores or channels able to accelerate the release of BLG. These pores were assumed to result from the presence of large amounts of protein molecules on the microsphere surface, that aggregate during microsphere formation at pH 5.2. Indeed, single adsorption experiments have shown that BLG had a higher affinity for the particle surface when the pH was close to the pI. Thus, reducing the solubility of a protein in the external aqueous phase allows the product of microspheres with a better encapsulation efficiency, although this benefit is provided by a strong adsorption of the protein on microsphere surface.

Mycoplasma penetrans bacteremia and primary antiphospholipid syndrome

Mycoplasma penetrans, a rare bacterium so far only found in HIV-infected persons, was isolated in the blood and throat of a non-HIV-infected patient with primary antiphospholipid syndrome (whose etiology and pathogenesis are unknown).

Number and size of stones in patients with asymptomatic and symptomatic gallstones and gallbladder carcinoma: a prospective study of 592 cases

The development of gallbladder carcinoma has been correlated with the presence of a single large gallstone in two retrospective studies. The objective of the present study was to determine the number and size of gallstones in patients with gallbladder carcinoma compared to asymptomatic and symptomatic female patients with gallstones. The following three groups of patients were included in this prospective trial: (A) 78 asymptomatic patients with gallstones; (B) 365 symptomatic patients with gallstones; and (C) 149 patients with gallbladder carcinoma. At the end of the operation, the resected gallbladder was opened and the number of stones counted. The maximum size of the stones was determined using calipers. Patients with gallbladder carcinoma were significantly older than patients in the other two groups (P <0.001). In the group with asymptomatic gallstones, there were significantly more patients with one single stone, whereas in the group with gallbladder carcinoma there were significantly more patients with multiple stones (more than 11; P <0.01). Patients with gallbladder carcinoma had significantly larger stones, regardless of the number of stones present (P <0.001). We postulate that the increase in the number and size of the stones among patients with gallbladder carcinoma could simply be an effect of aging or it could be a reflection of the long-term presence of stones in the gallbladder rather than some particular chemical or physical influence.

Liposome-entrapped ampicillin in the treatment of experimental murine listeriosis and salmonellosis

The tissue distribution of ampicillin entrapped in liposomes was studied in normal noninfected mice and showed that ampicillin concentrated mostly in the liver and spleen. Liposomate ampicillin was significantly more effective than free ampicillin in reducing splenic and hepatic bacterial counts in C57BL/Ka nude mice chronically infected with Listeria monocytogenes EGD. It was also significantly more effective than free ampicillin in reducing mortality in C57BL/6 mice acutely infected with Salmonella typhimurium C5. Comparison of the results with those previously obtained in the same experimental models with the same amounts of ampicillin bound to polyisohexylcyanoacrylate nanoparticles showed that liposomes were more effective than nanoparticles (M. Youssef, E. Fattal, M. J. Alonso, L. Roblot-Treupel, J. Sauzières, C. Tancrède, A. Omnès, P. Couvreur, and A. Andremont, Antimicrob. Agents Chemother. 32:1204-1207, 1988) in targeting ampicillin to the spleen but were less effective than nanoparticles in targeting ampicillin to the liver and reducing mortality in acute salmonellosis.

Studies on group B beta-hemolytic Streptococcus. II. Effects on pulmonary hemodynamics and vascular permeability in unanesthetized sheep

To study the effects of Group B beta-hemolytic Streptococcus on the pulmonary circulation and lung fluid balance, live and heat-killed bacteria and their toxin were infused into an awake sheep lung-lymph preparation. In every case, the response was biphasic; there was an initial period of marked pulmonary hypertension and high flow of protein-poor lymph associated with tachypnea, chills, and fever. A second phase followed during which pulmonary vascular pressures returned to near baseline and remained stable, but lymph flow remained high. The changes seen in the initial phase resemble the previously reported response to mechanically increased pulmonary vascular pressure and suggest that the increase in fluid filtration is secondary to increased microvascular pressure. During the second phase after toxin infusion, the increase in lung lymph flow was paralleled by an increase in lymph protein clearance. This cannot be accounted for by the hemodynamic changes alone an suggests that the permeability of lung microvascular walls to protein was increased. It is concluded that group B beta-hemolytic streptococcal toxin in the sheep model causes pulmonary hypertension and increased pulmonary vascular permeability.

A polysorbate-based non-ionic surfactant can modulate loading and release of beta-lactoglobulin entrapped in multiphase poly(DL-lactide-co-glycolide) microspheres

PURPOSE

The goal of the present paper was to investigate the role of a surfactant, Tween 20, in the modulation of the entrapment and release of beta-lactoglobulin (BLG) from poly (DL-lactide-co-glycolide) microspheres.

METHODS

Poly(DL-lactide-co-glycolide) microspheres containing BLG were prepared by a water-in-oil-in-water emulsion solvent procedure. Tween 20 was used as a surfactant in the internal aqueous phase of the primary emulsion. BLG entrapment efficiency and burst release were determined. Displacement of BLG from microsphere surface was followed by confocal microscopy observations and zeta potential measurements, whereas morphological changes were observed by freeze-fracture electron microscopy.

RESULTS

Tween 20 was shown to increase 2.8 fold the encapsulation efficiency of BLG without any modification of the stability of the first emulsion and the viscosity of the internal aqueous phase. In fact, Tween 20 was shown to be responsible for removing the BLG molecules that were adsorbed on the particle surface or very close to the surface as shown by confocal microscopy and zeta potential measurements. Tween 20 reduced the number of aqueous channels between the internal aqueous droplets as well as those communications with the external medium. Thus, the more dense structure of BLG microspheres could explain the decrease of the burst release.

CONCLUSIONS

These results constitute a step forward in the improvement of existing technology in controlling protein encapsulation and delivery from microspheres prepared by the multiple emulsion solvent evaporation method.

Optimization of the encapsulation and release of beta-lactoglobulin entrapped poly(DL-lactide-co-glycolide) microspheres

The goal of the present paper was to optimize the encapsulation of beta-lactoglobulin (BLG) within poly(lactide-co-glycolide) (PLGA) microparticles prepared by the multiple emulsion solvent evaporation method. The role of the pH of the external phase and the introduction of the surfactant Tween 20, in the modulation of the entrapment and release of BLG from microparticles, was studied. Reducing the solubility of BLG by decreasing the pH of the external phase to a value close to the pI of BLG resulted in a better encapsulation with, however, a larger burst release effect. By contrast, Tween 20 was shown to increase the encapsulation efficiency of BLG and reduce considerably the burst release effect. In fact, Tween 20 was shown to be responsible for removing the BLG molecules that were adsorbed on the particle surface. In addition, Tween 20 reduced the number of aqueous channels between the internal aqueous droplets as well as those communicating with the external medium. Thus, the more dense structure of BLG microspheres could explain the decrease in the burst release. These results constitute a step ahead in the improvement of an existing technology in controlling protein encapsulation and delivery from microspheres prepared by the multiple emulsion solvent evaporation method.

Ampicillin-loaded liposomes and nanoparticles: comparison of drug loading, drug release and in vitro antimicrobial activity

In this paper, we report the physico-chemical properties of negatively charged liposomes and of polyisohexylcyanoacrylate nanoparticles loaded with ampicillin. Although the carriers were of the same size (200 nm), drug-loading capacity was 20 times higher for nanoparticles than for liposomes. After freeze-drying or storage at +4 degrees C, no drug escaped from polymeric nanoparticles. On the other hand, in the same conditions, ampicillin leaked rapidly from liposomes. Drug release in foetal calf serum was gradual (of zero order) with nanoparticles, whereas it was rapid with liposomes. Finally, the antimicrobial activity of ampicillin-entrapped liposomes or nanoparticles was studied in vitro.

Photodegradation and phototoxicity studies of furosemide. Involvement of singlet oxygen in the photoinduced hemolysis and lipid peroxidation

The phototoxic diuretic drug furosemide (1), a 5-(aminosulfonyl)-4-chloro-2-[(2-furanylmethyl)-amino] benzoic acid is photolabile under aerobic and anaerobic conditions. Irradiation of a methanol solution of 1 under oxygen produces photoproducts 2, 3, 4 and singlet oxygen, while under argon the photoproducts 2 and 4 were isolated. A peroxidic unstable photoproduct was detected during the photolysis under oxygen atmosphere. The formation of singlet oxygen by photolysis of 1 was evidenced by trapping with 2,5-dimethylfuran (GC-mass), furfuryl alcohol and 1,3-cyclohexadiene-1,4-diethanoate (HPLC) as 1O2 scavengers and by the histidine test. Furosemide was screened in vitro at different concentrations for UV-Vis-induced phototoxic effects in a photohemolysis test, in the presence and absence of different radical scavengers, singlet oxygen and hydroxyl radical quenchers. However, furosemide photosensitized the peroxidation of linoleic acid, as monitored by the UV-detection of dienic hydroperoxides and it also photosensitized the oxidation of histidine. The photodegradation was catalyzed in the presence of human serum albumin. Studies on peripheral blood mononuclear and polymorphonuclear cells (lymphocytes and neutrophils) demonstrated no phototoxicity on these cell lines.

Clinical assessment of gingival hyperplasia in patients treated with nifedipine

Gingival hyperplasia caused by the use of nifedipine has been extensively reported. In this paper, the gingiva of 18 patients suffering from cardiopathy and treated with nifedipine were compared with those of 10 patients with cardiac disorders who had not been treated with calcium antagonists and with a no-treatment group of 12 patients. Nifedipine produced gingival hyperplasia, although patients who had not been treated with calcium antagonists also had mild hyperplasia. Hyperplasia first appeared in the interproximal areas, an observation which may be important for early detection. There was a direct correlation between the degree of hyperplasia and the bacterial plaque score. When we studied the influence of administration time and dose of nifedipine with the degree of hyperplasia, no statistically significant differences were found.

Studies on group B beta-hemolytic Streptococcus. I. Isolation and partial characterization of an extracellular toxin

To initiate an investigation into the biochemistry and mechanism of group B beta-hemolytic Streptococcus virulence, bacterial cultures grown in suspension were centrifuged, and the bacteria and media were subjected to extensive fractionation. Each fraction was assayed for physiologic activity by repeated intravenous infusion into adult unanesthetized sheep. Pulmonary artery pressure, arterial PO2, and rectal temperature were monitored. The media fraction, but not the bacteria, contained a component (molecular weight, 2 x 10(6)) composed of 845 carbohydrate and 16% protein with physiological activity. Two mg quantities, when infused, caused the pulmonary artery pressure to increase 100%, PO2 to decrease by 20% and chills and fever. The active component could be degraded by hot phenol-water extraction into a pure polysaccharide (molecular weight, 200,000). This lower molecular weight polysaccharide retained the identical physiologic properties when infused in the sheep. The degraded component precipitated with group B-specific antiserum. This study demonstrates that, in the sheep, a pure polysaccharide is the physiologically active part of a high-molecular-weight toxin synthesized by group B beta-hemolytic Streptococcus type III and that this component has a different carbohydrate composition from the group B capsular antigen.

Pulmonary hemodynamic and ultrastructural changes associated with Group B streptococcal toxemia in adult sheep and newborn lambs

A toxin isolated from Group B beta-hemolytic streptococci, Type III was infused into adult sheep and newborn lambs. A two-phased reaction was observed. There was an initial phase of pulmonary hypertension and high flow of protein-poor lymph. This was followed by a second phase when pressures returned to baseline but lymph flow remained twice the baseline values and protein concentration in lymph increased. During the second phase there was a significant increase in lymph protein clearance, suggestive of increased microvascular permeability to protein. The absolute granulocyte count decreased to 10% of baseline values by 60 min after the infusion, and was followed by a variable return to baseline. The sheep with the largest changes in protein clearance were those who had the slowest return to baseline values. Pathologic examination of lung tissue revealed there was capillary dilation, interstitial edema, and large numbers of granulocytes in the lungs. The basement membranes of both capillaries and arterioles showed disruption and widening, along with fragmentation of the internal elastic membrane. This study provides morphologic and physiologic evidence of increased pulmonary vascular permeability after injection of streptococcal toxin associated with granulocyte trapping in the lung. We postulate that granulocytes may be involved as mediators of the pulmonary vascular injury.

Chemotaxis of Leptospirillum ferrooxidans and other acidophilic chemolithotrophs: comparison with the Escherichia coli chemosensory system

Ni2+, Fe2+ and Cu2+ were attractants and aspartate was an apparent repellent for Leptospirillum ferrooxidans, a behaviour opposite to that for Escherichia coli. Membranes from L. ferrooxidans contained proteins with a molecular mass in the range of 80 kDa which were methylated in vitro. Methylation was stimulated in the presence of a membrane-free extract from E. coli, showing the response pattern expected for L. ferrooxidans, increased methylation by Ni2+, and demethylation by aspartate. This suggests the existence of sensory transducers having a common methylation domain with the E. coli methyl-accepting chemotaxis proteins. Total chromosomal DNA digests from L. ferrooxidans, Thiobacillus ferrooxidans and T. thiooxidans hybridized with probes containing different domains of the tar gene from E. coli, implying the presence of tar type genes in the acidophilic bacteria studied.