Unidentified curved bacilli in the stomach of patients with gastritis and peptic ulceration

Biopsy specimens were taken from intact areas of antral mucosa in 100 consecutive consenting patients presenting for gastroscopy. Spiral or curved bacilli were demonstrated in specimens from 58 patients. Bacilli cultured from 11 of these biopsies were gram-negative, flagellate, and microaerophilic and appeared to be a new species related to the genus Campylobacter. The bacteria were present in almost all patients with active chronic gastritis, duodenal ulcer, or gastric ulcer and thus may be an important factor in the aetiology of these diseases.

The Gene Ontology (GO) database and informatics resource

The Gene Ontology (GO) project (http://www. geneontology.org/) provides structured, controlled vocabularies and classifications that cover several domains of molecular and cellular biology and are freely available for community use in the annotation of genes, gene products and sequences. Many model organism databases and genome annotation groups use the GO and contribute their annotation sets to the GO resource. The GO database integrates the vocabularies and contributed annotations and provides full access to this information in several formats. Members of the GO Consortium continually work collectively, involving outside experts as needed, to expand and update the GO vocabularies. The GO Web resource also provides access to extensive documentation about the GO project and links to applications that use GO data for functional analyses.

Prevention of allogeneic fetal rejection by tryptophan catabolism

In 1953 Medawar pointed out that survival of the genetically disparate (allogeneic) mammalian conceptus contradicts the laws of tissue transplantation. Rapid T cell-induced rejection of all allogeneic concepti occurred when pregnant mice were treated with a pharmacologic inhibitor of indoleamine 2,3-dioxygenase (IDO), a tryptophan-catabolizing enzyme expressed by trophoblasts and macrophages. Thus, by catabolizing tryptophan, the mammalian conceptus suppresses T cell activity and defends itself against rejection.

Attempt to fulfil Koch's postulates for pyloric Campylobacter

A volunteer with histologically normal gastric mucosa received pyloric campylobacter by mouth. A mild illness developed, which lasted 14 days. Histologically proven gastritis was present on the tenth day after the ingestion of bacteria, but this had largely resolved by the fourteenth day. The syndrome of acute pyloric campylobacter gastritis is described. It is proposed that this disorder may progress to a chronic infection which predisposes to peptic ulceration.

Prospective double-blind trial of duodenal ulcer relapse after eradication of Campylobacter pylori

100 consecutive patients with both duodenal ulcer and Campylobacter pylori infection were followed up to see whether eradication of C pylori affected ulcer healing or relapse. Patients were randomly assigned to 8 weeks of treatment with cimetidine or colloidal bismuth subcitrate (CBS), with tinidazole or placebo being given concurrently from days 1 to 10, inclusive. Endoscopy, biopsy, and culture were done at entry, in weeks 10, 22, 34, and 62, and whenever symptoms recurred. There was no maintenance therapy. C pylori persisted in all of the cimetidine-treated patients and in 95% of those treated with cimetidine/tinidazole, but was eradicated in 27% of the CBS/placebo group and 70% of the CBS/tinidazole group. When C pylori persisted, 61% of duodenal ulcers healed and 84% relapsed. When C pylori was cleared 92% of ulcers healed (p less than 0.001) and only 21% relapsed during the 12 month follow-up period (p less than 0.0001).

Campylobacter pyloridis, gastritis, and peptic ulceration

Campylobacter pyloridis is a spiral bacterium which was seen by histopathologists several years before it was cultured in 1982 in Perth, Western Australia. It has unique cellular fatty acids, predominantly tetradecanoic acid and cis-11, 12 methylene octadecanoic acid. It also has a unique ultrastructure which is different from that of other campylobacters. C pyloridis possesses a powerful urease enzyme and produces large amounts of extracellular catalase. Both these features may be important virulence factors, allowing it to occupy a protected niche in the stomach below the mucus layer but above the gastric mucosa. Specific lesions are found in the gastric mucosa, and ultrastructural studies show the presence of adherence pedestals identical with those found with enteropathogenic Escherichia coli of the intestine. Histological examination of gastric biopsy tissue has shown that C pyloridis is strongly associated with active chronic gastritis, when polymorphonuclear leucocytes are present, and is not found on normal mucosa except when a biopsy specimen from elsewhere in the stomach shows active chronic gastritis. When patients with symptoms caused by gastritis are identified dual antibacterial treatment, combining the action of bismuth in the stomach with a systemic antibiotic, can eradicate C pyloridis, with remission of symptoms and restoration of normal epithelial morphology. Most peptic ulcers relapse after modern acid reducing treatment, and antibacterial treatment may be beneficial in preventing relapse.

Pyloric Campylobacter infection and gastroduodenal disease

In 1982, a new spiral Gram-negative bacterium which was similar to those of the genus Campylobacter was isolated from the gastric mucosa of 11 patients with gastritis. From then on, the organism was isolated in a further 114 of 267 patients who underwent antral biopsy in Fremantle Hospital between January 1983 and September 1984. During 1984, the bacterium was cultured from 88% of patients in whom it was detected histologically, and was not cultured from any patient with histologically normal gastric mucosa. The new bacterium, pyloric campylobacter, grew in three days on brain-heart infusion blood-agar at 37 degrees C in an atmosphere with added CO2. All isolates tested were sensitive to penicillin, erythromycin, tetracycline, cephalosporins, gentamicin and bismuth citrate; 80% of isolates were sensitive to metronidazole or tinidazole. It is suggested that pyloric campylobacter infection is a major factor in the causation of dyspeptic disease and peptic ulceration. Antibacterial regimens directed against the bacterium may provide a permanent cure for these chronic disorders.

Transhiatal esophagectomy: clinical experience and refinements

OBJECTIVE

To review the authors' clinical experience with transhiatal esophagectomy (THE) and the refinements in this procedure that have evolved.

BACKGROUND

Increased use of THE during the past two decades has generated controversy about the merits and safety of this approach compared with transthoracic esophageal resection. The authors' large THE experience provides a valuable basis for benchmarking data regarding the procedure.

METHODS

The results of THE were analyzed retrospectively using the authors' prospectively established esophageal resection database and follow-up information on these patients.

RESULTS

From 1976 to 1998, THE was performed in 1085 patients, 26% with benign disease and 74% with cancer. The procedure was possible in 98.6% of cases. Stomach was the esophageal substitute in 96%. The hospital mortality rate was 4%. Blood loss averaged 689 cc. Major complications were anastomotic leak (13%), atelectasis/pneumonia (2%), intrathoracic hemorrhage, recurrent laryngeal nerve paralysis, chylothorax, and tracheal laceration (<1% each). Actuarial survival of patients with carcinoma equaled or exceeded that reported after transthoracic esophagectomy. Late functional results were good or excellent in 70%. With preoperative pulmonary and physical conditioning, a side-to-side stapled cervical esophagogastric anastomosis (<3% incidence of leak), and postoperative epidural anesthesia, the need for an intensive care unit stay has been eliminated and the length of stay reduced to 7 days.

CONCLUSION

THE is possible in most patients requiring esophageal resection and can be performed with greater safety and fewer complications than the traditional transthoracic approaches.

Urea protects Helicobacter (Campylobacter) pylori from the bactericidal effect of acid

Colonization of the stomach with Helicobacter (Campylobacter) pylori is common in patients with duodenal ulcer disease, which is known for its high acid secretion. Although the bacterium is usually isolated by culture of a gastric biopsy specimen, viable organisms may sometimes be found in the acidic gastric juice. It was postulated that urease, by generating ammonia, protected H. pylori from acid. To test this hypothesis, the pH susceptibility of H. pylori, Proteus mirabilis, and the urease-negative Campylobacter jejuni was examined in the presence and absence of urea. It was found that without urea the three bacteria were all highly susceptible to acid. In striking contrast, the addition of 5 mmol/L of urea completely protected H. pylori but not P. mirabilis or C. jejuni from pH values as low as 1.5. Furthermore, the protective effect of urea on H. pylori was found with urea concentrations as low as 0.05 mmol/L. It is concluded that the high urease activity of H. pylori enables it to survive in gastric acid.

Eliminating the cervical esophagogastric anastomotic leak with a side-to-side stapled anastomosis

BACKGROUND

Although the acute postoperative complications of a cervical esophagogastric anastomosis are less than those with an intrathoracic esophageal anastomosis, the long-term sequelae of a cervical anastomotic leak are not as minor as initially reported. Nearly 50% of cervical anastomotic leaks result in an anastomotic stricture, and the subsequent need for chronic dilatations negates the merits of an operation intended to restore comfortable swallowing.

OBJECTIVE

This study was undertaken to determine whether construction of a side-to-side stapled cervical esophagogastric anastomosis after transhiatal esophagectomy could reliably eliminate the majority of anastomotic leaks.

METHODS

In 114 consecutive patients undergoing transhiatal esophagectomy, a functional side-to-side cervical esophagogastric anastomosis was constructed with the Auto Suture Endo-GIA II stapler (United States Surgical Corporation, Auto Suture Company Division, Norwalk, Conn) applied directly through the cervical wound. This side-to-side stapled anastomosis has 3 rows of staples. Early postoperative anastomotic morbidity, subsequent need for anastomotic dilatations, and patient satisfaction with swallowing were evaluated.

RESULTS

Before the side-to-side stapled anastomosis, the incidence of cervical esophagogastric anastomosis leak in over 1000 patients undergoing transhiatal esophagectomy having a manually sewn anastomosis varied from 10% to 15%. Among the 111 survivors of transhiatal esophagectomy and a side-to-side stapled anastomosis, there were 3 (2.7%) clinically significant anastomotic leaks. This lowered incidence of leaks has contributed to reduction in the average length of stay after an uncomplicated transhiatal esophagectomy to 7 days and has provided more comfortable swallowing, ease of subsequent esophageal dilatations, and greater patient satisfaction.

CONCLUSIONS

Construction of the cervical esophagogastric anastomosis with a side-to-side stapled anastomosis greatly reduces the frequency of anastomotic leaks and later strictures. The side-to-side stapled anastomosis is a major technical advance in the progression of refinements of transhiatal esophagectomy and a cervical esophagogastric anastomosis.

Duodenal ulcer treated with Helicobacter pylori eradication: seven-year follow-up

The long-term benefits of Helicobacter pylori-eradication treatment (HET) in H pylori-associated duodenal ulcer are unclear. We followed up patients with duodenal ulcers from a trial of H pylori eradication in 1985-86. 63 of 78 patients (81%) were reviewed clinically and had upper gastrointestinal endoscopy with gastric antral biopsy. Of 35 patients previously rendered H pylori negative, 32 (92%) remained H pylori negative after 7.1 years (mean). All patients initially H pylori positive remained infected, unless HET was given in the interim. Duodenal ulceration was found in 20% (5 out of 25) of patients remaining H pylori-positive, compared with 3% (1 of 38) of H pylori-negative patients (p < 0.05). The reduction of duodenal ulcer relapse obtained from H pylori eradication in H pylori-associated duodenal ulcer extends to at least 7 years after treatment, and is likely to be due to freedom from H pylori infection. However, duodenal ulcer may recur in patients rendered H pylori negative, due to factors other than reinfection with H pylori.

The peopling of the Pacific from a bacterial perspective

Two prehistoric migrations peopled the Pacific. One reached New Guinea and Australia, and a second, more recent, migration extended through Melanesia and from there to the Polynesian islands. These migrations were accompanied by two distinct populations of the specific human pathogen Helicobacter pylori, called hpSahul and hspMaori, respectively. hpSahul split from Asian populations of H. pylori 31,000 to 37,000 years ago, in concordance with archaeological history. The hpSahul populations in New Guinea and Australia have diverged sufficiently to indicate that they have remained isolated for the past 23,000 to 32,000 years. The second human expansion from Taiwan 5000 years ago dispersed one of several subgroups of the Austronesian language family along with one of several hspMaori clades into Melanesia and Polynesia, where both language and parasite have continued to diverge.

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Expression of angiostatin cDNA in a murine fibrosarcoma suppresses primary tumor growth and produces long-term dormancy of metastases

Tumor growth and metastasis are angiogenesis dependent. Previously, we reported that angiostatin, a potent angiogenesis inhibitor, produced by a primary Lewis lung carcinoma suppressed its growth of lung metastases (O'Reilly, M.S., L. Holmgren, Y. Shing, C. Chen, R.A. Rosenthal, M. Moses, W.S. Lane, Y. Cao, E.H. Sage, and J. Folkman. 1994. Cell. 79:315-328). Now we show that a shift of balance of tumor angiogenesis by gene transfer of a cDNA coding for mouse angiostatin into murine T241 fibrosarcoma cells suppresses primary and metastatic tumor growth in vivo. Implantation of stable clones expressing mouse angiostatin in C57Bl6/J mice inhibits primary tumor growth by an average of 77%. After removal of primary tumors, the pulmonary micrometastases in approximately 70% of mice remain in a microscopic dormant and avascular state for the duration of the experiments, e.g., 2-5 mo. The tumor cells in the dormant micrometastases exhibit a high rate of apoptosis balanced by a high proliferation rate. Our study, to our knowledge, for the first time shows the diminished growth of lung metastases after removal of the primary tumor, suggesting that metastases are self-inhibitory by halting angiogenesis. Our data may also provide a novel approach for cancer therapy by antiangiogenic gene therapy with a specific angiogenesis inhibitor.

Prevention of nitroimidazole resistance in Campylobacter pylori by coadministration of colloidal bismuth subcitrate: clinical and in vitro studies

One hundred patients with duodenal ulceration and Campylobacter pylori in their stomach were entered into a double blind placebo controlled prospective study. Treatment schedules were cimetidine and placebo, or cimetidine and tinidazole, or colloidal bismuth subcitrate (CBS) and placebo, or CBS and tinidazole. Seventeen per cent of isolates of C pylori obtained at the first endoscopy were resistant to tinidazole and 70% of the second isolates from patients given cimetidine and tinidazole became tinidazole resistant. Suspensions of nitroimidazole sensitive cultures of C pylori showed that three of 22 isolates had a nitroimidazole resistant subpopulation. In patients who healed and remained free of C pylori after treatment ulcers recurred less often than in patients who healed but retained C pylori (23% v 73% over 12 months, p less than 0.001).

Enzyme-linked immunosorbent assay for Campylobacter pyloridis: correlation with presence of C. pyloridis in the gastric mucosa

Antibody to Campylobacter pyloridis was measured by ELISA in the sera of 160 patients from whom gastric biopsy specimens were also obtained. The antigen was an acid-glycine extract of C. pyloridis, and titers ranged from 80 to 22,000 ELISA units (EU). Of 117 patients in whom C. pyloridis was detected microbiologically or histologically, 87 (74%) had a titer greater than or equal to 300 EU, and only one had a titer less than 150 EU. Of 43 patients in whom C. pyloridis was not detected, only two (5%) had a titer greater than 300 EU. Thus, for a titer of 300 EU the ELISA test had a specificity of 97% and a sensitivity of 81%. At 150 EU the specificity was 78%, and the sensitivity was 99%. Histological diagnosis of active chronic gastritis was associated with a high median ELISA titer (485 E), chronic gastritis with a much lower titer (150 EU), and normal histology with a titer of 110 EU. Discriminating use of this serological test could be of assistance to detect C. pyloridis in the gastric mucosa.

Mercury released from dental "silver" fillings provokes an increase in mercury- and antibiotic-resistant bacteria in oral and intestinal floras of primates

In a survey of 640 human subjects, a subgroup of 356 persons without recent exposure to antibiotics demonstrated that those with a high prevalence of Hg resistance in their intestinal floras were significantly more likely to also have resistance to two or more antibiotics. This observation led us to consider the possibility that mercury released from amalgam ("silver") dental restorations might be a selective agent for both mercury- and antibiotic-resistant bacteria in the oral and intestinal floras of primates. Resistances to mercury and to several antibiotics were examined in the oral and intestinal floras of six adult monkeys prior to the installation of amalgam fillings, during the time they were in place, and after replacement of the amalgam fillings with glass ionomer fillings (in four of the monkeys). The monkeys were fed an antibiotic-free diet, and fecal mercury concentrations were monitored. There was a statistically significant increase in the incidence of mercury-resistant bacteria during the 5 weeks following installation of the amalgam fillings and during the 5 weeks immediately following their replacement with glass ionomer fillings. These peaks in incidence of mercury-resistant bacteria correlated with peaks of Hg elimination (as high as 1 mM in the feces) immediately following amalgam placement and immediately after replacement of the amalgam fillings. Representative mercury-resistant isolates of three selected bacterial families (oral streptococci, members of the family Enterobacteriaceae, and enterococci) were also resistant to one or more antibiotics, including ampicillin, tetracycline, streptomycin, kanamycin, and chloramphenicol. While such mercury- and antibiotic-resistant isolates among the staphylococci, the enterococci, and members of the family Enterobacteriaceae have been described, this is the first report of mercury resistance in the oral streptococci. Many of the enterobacterial strains were able to transfer mercury and antibiotic resistances together to laboratory bacterial recipients, suggesting that the loci for these resistances are genetically linked. Our findings indicate that mercury released from amalgam fillings can cause an enrichment of mercury resistance plasmids in the normal bacterial floras of primates. Many of these plasmids also carry antibiotic resistance, implicating the exposure to mercury from dental amalgams in an increased incidence of multiple antibiotic resistance plasmids in the normal floras of nonmedicated subjects.

Antibacterial action of bismuth in relation to Campylobacter pyloridis colonization and gastritis

Colloidal bismuth subcitrate (CBS, De-Nol) heals duodenal ulcers but with a lower relapse rate than cimetidine, perhaps due to inhibition of Campylobacter pyloridis (CP) organisms. To test this hypothesis we studied gastric mucosal histology in three groups of ulcer patients treated with either cimetidine, CBS, or CBS in combination with an antibiotic. Cimetidine had no effect on CP or gastric mucosal histology but with CBS therapy there was a significant reduction in the number of bacteria (p less than 0.0001). However, relapse of both CP infection and gastritis usually occurred once CBS was withdrawn. When CBS was combined with amoxycillin or tinidazole, long-term disappearance of both CP bacteria and gastritis was achieved (p less than 0.0001). In ultrastructural studies 30-90 min after single oral doses of CBS or bismuth subsalicylate, CP had detached from the gastric epithelial cells and exhibited structural degradation associated with the selective deposition of a particulate bismuth complex within and upon the surface of the organisms. In vitro, CP and other campylobacters were inhibited by bismuth compounds at 25 mg/l but they were resistant to cimetidine and ranitidine. CBS has a powerful antibacterial effect against CP but relapse of infection is common after CBS alone. In combination with antibiotics however, eradication of CP and long-term healing of gastritis occurs. In such cases the gastroduodenal mucosa is intact, and less likely to ulcerate.

Esophagectomy for achalasia: patient selection and clinical experience

BACKGROUND

In 1989, we predicted an increasing number of esophagectomies for megaesophagus and for recurrent symptoms after prior esophagomyotomy or balloon dilatation for achalasia. Patient selection in this group is challenging, as the potential operative morbidity of an esophagectomy must be weighed against the expected clinical outcome after a redo esophagomyotomy or alternative procedures designed to salvage the native esophagus.

METHODS

The hospital records of 93 patients undergoing esophagectomy for achalasia during the past 20 years were reviewed retrospectively and the results of operation assessed using our prospectively established Esophageal Resection Database and follow-up information obtained through personal contact with the patients.

RESULTS

Patient age averaged 51 years. Indications for esophagectomy included tortuous megaesophagus (64%), failure of prior myotomy (63%), and associated reflux stricture (7%). Ninety-four percent of the patients underwent a transhiatal esophagectomy. Stomach was used as the esophageal substitute in 91% cases. Intraoperative blood loss averaged 672 mL. Postoperative length of stay averaged 12.5 days. Major complications included anastomotic leak (10%), recurrent laryngeal nerve injury (5%), delayed mediastinal bleeding requiring thoracotomy (2%), and chylothorax (2%). There were 2 hospital deaths (2%) from respiratory insufficiency and sepsis. Follow-up has averaged 38 months. In all, 95% of patients eat well; nearly 50% have required an anastomotic dilatation; troublesome regurgitation has been rare; and 4% have refractory postvagotomy dumping.

CONCLUSIONS

Esophagectomy, preferably through a transhiatal approach, is generally safe and effective therapy in selected patients with achalasia. Unique technical considerations include difficulty encircling the dilated cervical esophagus, deviation of the esophagus into the right chest, large aortic esophageal arteries, and adherence of the exposed esophageal submucosa to the adjacent aorta after prior myotomy.

Development of an Adhesion Assay and Characterization of an Adhesion-Deficient Mutant of Pseudomonas fluorescens

A sand column adhesion assay was developed which distinguishes the adhesion abilities of a number of pseudomonads isolated from fine sandy loam. Pseudomonas fluorescens Pf0-1 which adhered at >90% of the total cells added was subjected to transposon Tn 5 insertion mutagenesis. From 2,500 Pf0-1::Tn 5 mutants examined in the sand column assay, two adhesion-deficient Pf0-1 mutants showing <50% attachment were isolated. Marker exchange analysis of one of these mutants, Pf0-5, confirmed that the decreased adhesion was linked to the Tn 5 insertion in the chromosome. The growth rate of Pf0-5 in enriched media and sterile soil was similar to that of the wild type; in minimal medium, however, Pf0-5 grew faster. In a soil column assay, less Pf0-5 than wild-type bacteria were recovered, suggesting a decreased ability to persist in soil. A 34-kilodalton major outer membrane protein present in the wild type was missing in Pf0-5. Transmission electron microscopy of the cell surface revealed that the wild-type possessed polar flagella which were absent in the mutant.

High frequency of antimicrobial resistance in human fecal flora

The frequency of resistance to seven different antimicrobial agents was examined in the aerobic gram-negative gut flora of over 600 individuals from hospitals, from laboratories where antibiotics were used, and from urban and rural communities. In a majority (62.5%) of fecal samples from people without a recent history of taking antibiotics, 10% or more of the total organisms were resistant to at least one of the antibiotics. In about 40% of the samples, resistance to more than one drug was present at this level. More than one-third of the samples contained resistant organisms comprising 50% or more of the total flora examined. Organisms with coresistance to multiple drugs were found frequently. Individuals taking antibiotics produced more samples with a higher proportion (greater than 50%) of resistant bacteria, and these samples also had a significantly greater number of different resistance determinants. This extensive study revealed a high prevalence of resistant bacteria in the gut flora of ambulatory and hospitalized individuals whether or not they were taking antibiotics.

Site and sensitivity for stimulation of hypoxic pulmonary vasoconstriction

Rat lungs were perfused in an in vitro circuit with separate control of alveolar and pulmonary arterial O2 tension. With perfusion flow constant, the hypoxic pulmonary vasoconstrictor (HPV) response was measured as changes of perfusion pressure. HPV was a function of both alveolar O2 tension (PvO2) and was described by a double sigmoid response surface. Where RA-v is this pressure response expressed as a percent of the maximum, the linearized form of the response surface is given by log [RA-v/(100-RA-v)] = 3.93 - 1.029 (log PvO2) - 1.623 (log PAO2). From this relationship it was concluded that 1) HPV is determined by PAO2 and PvO2; 2) the fundamental stimulus-response relationship is a sigmoid with a 50% response when both PAO2 and PvO2 are 30.3 Torr; 3) PAO2 has a greater effect than PvO2 due in part to the geometry of the vascular wall but principally due to O2 exchange between alveolar gas and blood in small pulmonary arteries; 4) there is not a localized sensor for HPV (the response is accounted for by each smooth muscle cell in the pulmonary arterial wall responding to the O2 tension in its vicinity); and 5) the characteristics of the response suggest that the cell sensor resembles a cytochrome.

The relation of Helicobacter pylori to gastric adenocarcinoma and lymphoma: pathophysiology, epidemiology, screening, clinical presentation, treatment, and prevention

Helicobacter pylori infection may be the most common chronic bacterial infection worldwide; however, the prevalence varies between countries and is usually linked to socioeconomic conditions. Gastric cancer is one of the most frequent cancers in developing countries and usually about the seventh most common in developed countries. This article explores the relation of H. pylori to gastric adenocarcinoma and lymphoma. The pathophysiology, epidemiology, screening, clinical presentation, treatment, and prevention are discussed.