The Caribbean and Mesoamerica Biogeochemical Isotope Overview (CAMBIO)

The Caribbean & Mesoamerica Biogeochemical Isotope Overview (CAMBIO) is an archaeological data community designed to integrate published biogeochemical data from the Caribbean, Mesoamerica, and southern Central America to address questions about dynamic interactions among humans, animals, and the environment in the region over the past 10,000 years. Here we present the CAMBIO human dataset, which consists of more than 16,000 isotopic measurements from human skeletal tissue samples (δ13C, δ15N, δ34S, δ18O, 87Sr/86Sr, 206/204Pb, 207/204Pb, 208/204Pb, 207/206Pb) from 290 archaeological sites dating between 7000 BC to modern times. The open-access dataset also includes detailed chronological, contextual, and laboratory/sample preparation information for each measurement. The collated data are deposited on the open-access CAMBIO data community via the Pandora Initiative data platform ( https://pandoradata.earth/organization/cambio ).

Trans-Holocene Bayesian chronology for tree and field crop use from El Gigante rockshelter, Honduras

El Gigante rockshelter in western Honduras provides a deeply stratified archaeological record of human-environment interaction spanning the entirety of the Holocene. Botanical materials are remarkably well preserved and include important tree (e.g., ciruela (Spondias), avocado (Persea americana)) and field (maize (Zea mays), beans (Phaseolus), and squash (Cucurbita)) crops. Here we provide a major update to the chronology of tree and field crop use evident in the sequence. We report 375 radiocarbon dates, a majority of which are for short-lived botanical macrofossils (e.g., maize cobs, avocado seeds, or rinds). Radiocarbon dates were used in combination with stratigraphic details to establish a Bayesian chronology for ~9,800 identified botanical samples spanning the last 11,000 years. We estimate that at least 16 discrete intervals of use occurred during this time, separated by gaps of ~100-2,000 years. The longest hiatus in rockshelter occupation was between ~6,400 and 4,400 years ago and the deposition of botanical remains peaked at ~2,000 calendar years before present (cal BP). Tree fruits and squash appeared early in the occupational sequence (~11,000 cal BP) with most other field crops appearing later in time (e.g., maize at ~4,400 cal BP; beans at ~2,200 cal BP). The early focus on tree fruits and squash is consistent with early coevolutionary partnering with humans as seed dispersers in the wake of megafaunal extinction in Mesoamerica. Tree crops predominated through much of the Holocene, and there was an overall shift to field crops after 4,000 cal BP that was largely driven by increased reliance on maize farming.

A genetic history of the pre-contact Caribbean

Humans settled the Caribbean about 6,000 years ago, and ceramic use and intensified agriculture mark a shift from the Archaic to the Ceramic Age at around 2,500 years ago1-3. Here we report genome-wide data from 174 ancient individuals from The Bahamas, Haiti and the Dominican Republic (collectively, Hispaniola), Puerto Rico, Curaçao and Venezuela, which we co-analysed with 89 previously published ancient individuals. Stone-tool-using Caribbean people, who first entered the Caribbean during the Archaic Age, derive from a deeply divergent population that is closest to Central and northern South American individuals; contrary to previous work4, we find no support for ancestry contributed by a population related to North American individuals. Archaic-related lineages were >98% replaced by a genetically homogeneous ceramic-using population related to speakers of languages in the Arawak family from northeast South America; these people moved through the Lesser Antilles and into the Greater Antilles at least 1,700 years ago, introducing ancestry that is still present. Ancient Caribbean people avoided close kin unions despite limited mate pools that reflect small effective population sizes, which we estimate to be a minimum of 500-1,500 and a maximum of 1,530-8,150 individuals on the combined islands of Puerto Rico and Hispaniola in the dozens of generations before the individuals who we analysed lived. Census sizes are unlikely to be more than tenfold larger than effective population sizes, so previous pan-Caribbean estimates of hundreds of thousands of people are too large5,6. Confirming a small and interconnected Ceramic Age population7, we detect 19 pairs of cross-island cousins, close relatives buried around 75 km apart in Hispaniola and low genetic differentiation across islands. Genetic continuity across transitions in pottery styles reveals that cultural changes during the Ceramic Age were not driven by migration of genetically differentiated groups from the mainland, but instead reflected interactions within an interconnected Caribbean world1,8.

Early isotopic evidence for maize as a staple grain in the Americas

Maize is a cultigen of global economic importance, but when it first became a staple grain in the Americas, was unknown and contested. Here, we report direct isotopic dietary evidence from 52 radiocarbon-dated human skeletons from two remarkably well-preserved rock-shelter contexts in the Maya Mountains of Belize spanning the past 10,000 years. Individuals dating before ~4700 calendar years before present (cal B.P.) show no clear evidence for the consumption of maize. Evidence for substantial maize consumption (~30% of total diet) appears in some individuals between 4700 and 4000 cal B.P. Isotopic evidence after 4000 cal B.P. indicates that maize became a persistently used staple grain comparable in dietary significance to later maize agriculturalists in the region (>70% of total diet). These data provide the earliest definitive evidence for maize as a staple grain in the Americas.

Diurnal intraocular pressure fluctuation and its risk factors in angle-closure and open-angle glaucoma

PURPOSE

To evaluate intraocular pressure (IOP) fluctuation during office hours and its predictive factors in untreated primary angle-closure suspects (PACS); post-iridotomy primary angle closure (PAC) and primary angle-closure glaucoma (PACG) eyes with or without IOP-lowering medication(s) as appropriate and medically treated primary open-angle glaucoma (POAG) eyes.

METHODS

One-hundred seventeen eyes (29 PACS, 30 PAC, 28 PACG, and 30 POAG) of 117 patients were included in this cross-sectional study. The subjects underwent hourly IOP measurements with Goldmann tonometer from 0800 to 1700 hours. Subjects with PAC and PACG had laser peripheral iridotomy at least 2 weeks prior to the inclusion. SD of office-hour IOP readings was the main outcome measure.

RESULTS

IOP fluctuation differed between the groups (P=0.01; Kruskal-Wallis Test). Post hoc Mann-Whitney U-tests showed significantly less IOP fluctuation in PACS compared with PACG (P<0.01). Peak office-hour IOP was observed in the morning in untreated subjects and in the early afternoon in treated subjects. A stepwise linear regression model identified the presence of peripheral anterior synechiae (PAS), thickness of lens, large vertical cup-to-disc ratio (VCDR), and PAC category as significant predictive factors associated with office-hour IOP fluctuation.

CONCLUSIONS

Diurnal IOP fluctuation in asymptomatic PACSs was less than that in treated PACG subjects and was at least comparable to that in treated PAC and POAG subjects. The greater the amount of PAS, the thicker the lens, the larger the VCDR, the greater was the IOP fluctuation during office hours.

Arylpropanolamines: Selective β3 agonists arising from strategies to mitigate phase I metabolic transformations

Utilization of N-substituted-4-hydroxy-3-methylsulfonanilidoethanolamines 1 as selective beta(3) agonists is complicated by their propensity to undergo metabolic oxidative N-dealkylation, generating 0.01-2% of a very potent alpha(1) adrenergic agonist 2. A summary of the SAR for this hepatic microsomal conversion precedes presentation of strategies to maintain the advantages of chemotype 1 while mitigating the consequences of N-dealkylation. This effort led to the identification of 4-hydroxy-3-methylsulfonanilidopropanolamines 15 for which the SAR for the unique stereochemical requirements for binding to the beta adrenergic receptors culminated in the identification of the potent, selective beta(3) agonist 15f.

BMS-201620: a selective beta 3 agonist

A series of N-(4-hydroxy-3-methylsulfonanilidoethanol)arylglycinamides were prepared and evaluated for their human beta3 adrenergic receptor agonist activity. SAR studies led to the identification of BMS-201620 (39), a potent beta3 full agonist (Ki = 93 nM, 93% activation). Based on its favorable safety profile, BMS-201620 was chosen for clinical evaluation.

Low frequency of myocilin mutations in Indian primary open-angle glaucoma patients

Glaucoma is one of the major causes of blindness in the Indian population. Mutations in the myocilin (MYOC) gene have been reported in different populations. However, reports on MYOC mutations in Indian primary open-angle glaucoma (POAG) patients and juvenile open-angle glaucoma (JOAG) patients are sparse. We therefore screened 100 unrelated POAG/JOAG patients for MYOC mutations. Patients with POAG/JOAG were clinically diagnosed. Genomic DNA from such patients was collected and studied for MYOC mutations by direct sequencing. Nucleotide variations were compared with unrelated healthy controls by restriction enzyme digestion. Secondary structure prediction for the sequence variants was performed by Chou-Fasman method. A novel mutation in exon 1 (144 G-->Alpha) resulting in Gln48His substitution was observed in 2% of the patients. Four other polymorphisms were also observed. The novel mutation was seen in four other affected family members of a JOAG patient. The novel mutation was found to alter the secondary structure in the glycosaminoglycan initiation site of the protein. MYOC mutations were found in 2% of the population studied. MYOC gene may not be playing a significant role in causing POAG in the Indian population.

Pseudoexfoliation in South India

AIM

To study the profile of pseudoexfoliation in a population based study.

METHOD

2850 consecutive subjects aged 40 years or older from a population based survey in a rural area of southern India underwent complete ophthalmic evaluation including history, visual acuity testing, refraction, slit lamp examination, applanation tonometry, gonioscopy, and dilated examination of the lens (including LOCS II grading of cataract), fundus, and optic disc. Patients with pseudoexfoliation syndrome were identified and their data were analysed with respect to age, sex, intraocular pressure, gonioscopic grading, cataract, and optic neuropathy.

RESULTS

108 subjects had pseudoexfoliation syndrome (3.8 %). There was a significant increase in prevalence with age but no sex predilection. The condition was unilateral in 53 cases (49.1%) and bilateral in 55 cases (50.9%). 18 cases with pseudoexfoliation (16.7%) had high intraocular pressure (>21 mm Hg), 16 cases (14.8%) had occludable angles, and 14 cases (13%) had pseudoexfoliation glaucoma. There was a significantly higher prevalence of cataract among people with pseudoexfoliation compared to those without pseudoexfoliation (p = 0.014).

CONCLUSION

The prevalence of pseudoexfoliation syndrome in the rural population of south India was 3.8%. Raised intraocular pressure was seen in 16.7% of people with pseudoexfoliation and glaucoma was present in 13%.

BMS-196085: a potent and selective full agonist of the human beta(3) adrenergic receptor

A series of 4-hydroxy-3-methylsulfonanilido-1,2-diarylethylamines were prepared and evaluated for their human beta(3) adrenergic receptor agonist activity. SAR studies led to the identification of BMS-196085 (25), a potent beta(3) full agonist (K(i)=21 nM, 95% activation) with partial agonist (45%) activity at the beta(1) receptor. Based on its desirable in vitro and in vivo properties, BMS-196085 was chosen for clinical evaluation.

Beta 3 agonists. Part 1: evolution from inception to BMS-194449

Screening of the BMS collection identified 4-hydroxy-3-methylsulfonanilidoethanolamines as full beta 3 agonists. Substitution of the ethanolamine nitrogen with a benzyl group bearing a para hydrogen bond acceptor promoted beta(3) selectivity. SAR elucidation established that highly selective beta(3) agonists were generated upon substitution of C(alpha) with either benzyl to form (R)-1,2-diarylethylamines or with aryl to generate 1,1-diarylmethylamines. This latter subset yielded a clinical candidate, BMS-194449 (35).(1)

Dental caries and the microbial ecology of dental plaque: a review of recent advances

Our understanding of the microbial ecology of dental plaque has rapidly grown with recent developments in the techniques of molecular biology. In particular, knowledge of the mechanisms underlying the acquisition, establishment, pathogenicity, and evolution of the group of organisms responsible for dental caries--the mutans streptococci--has expanded to the point that we can now contemplate new opportunities for caries prevention. These advances reinforce developing concepts of dental plaque as an interdependent, interacting community of specialised organisms with an ability to rapidly adapt conferred by gene structures that facilitate the expeditious modular rearrangement of protein components.

Incorporating Geological Effects in Modeling of Revegetation Strategies for Salt-Affected Landscapes

/ This paper synthesizes results of research into the impact that major faults have on dryland salinity and the development of revegetation treatments in the wheatbelt of Western Australia. Currently, landscape planning does not routinely incorporate geology, but this research shows that faults can have a dramatic impact on land and stream salinization and on the effectiveness of revegetation treatments, and evidence exists that other geological features can have a similar influence. This research shows that faults can be identified from airborne magnetic data, they can be assigned a characteristic hydraulic conductivity based on simple borehole tests, and four other geological features that are expected to affect land and stream salinity could be identified in airborne geophysical data. A geological theme map could then be created to which characteristic hydraulic conductivities could be assigned for use in computer groundwater models to improve prediction of the effectiveness of revegetation treatments and thus enhance the landscape planning process. The work highlights the difficulties of using standard sampling and statistical techniques to investigate regional phenomena and presents an integrated approach combining small-scale sampling with broad-scale observations to provide input into a modeling exercise. It is suggested that such approaches are vital if landscape- and regional-scale processes are to be understood and managed. The way in which the problem is perceived (holistically or piecemeal) affects the way treatments are designed and their effectiveness: past approaches have failed to integrate the various scales and processes involved. Effective solutions require an integrated holistic response.KEY WORDS: Dryland salinity; Geology; Landscape; Revegetation integrationhttp://link.springer-ny.com/link/service/journals/00267/bibs/24n1p99.html

FGF-2 enhances intestinal stem cell survival and its expression is induced after radiation injury

Fibroblast growth factors (FGFs) have mitogenic activity toward a wide variety of cells of mesenchymal, neuronal, and epithelial origin and regulate events in normal embryonic development, angiogenesis, wound repair, and neoplasia. FGF-2 is expressed in many normal adult tissues and can regulate migration and replication of intestinal epithelial cells in culture. However, little is known about the effects of FGF-2 on intestinal epithelial stem cells during either normal epithelial renewal or regeneration of a functional epithelium after injury. In this study, we investigated the expression of FGF-2 in the mouse small intestine after irradiation and determined the effect of exogenous FGF-2 on crypt stem cell survival after radiation injury. Expression of FGF-2 mRNA and protein began to increase at 12 h after gamma-irradiation, and peak levels were observed from 48 to 120 h after irradiation. At all times after irradiation, the higher molecular mass isoform ( approximately 24 kDa) of FGF-2 was the predominant form expressed in the small intestine. Immunohistochemical analysis of FGF-2 expression after radiation injury demonstrated that FGF-2 was predominantly found in the mesenchyme surrounding regenerating crypts. Exogenous recombinant human FGF-2 (rhFGF-2) markedly enhanced crypt stem cell survival when given before irradiation. We conclude that expression of FGF-2 is induced by radiation injury and that rhFGF-2 can enhance crypt stem cell survival after subsequent injury.

An MTP inhibitor that normalizes atherogenic lipoprotein levels in WHHL rabbits

Patients with abetalipoproteinemia, a disease caused by defects in the microsomal triglyceride transfer protein (MTP), do not produce apolipoprotein B-containing lipoproteins. It was hypothesized that small molecule inhibitors of MTP would prevent the assembly and secretion of these atherogenic lipoproteins. To test this hypothesis, two compounds identified in a high-throughput screen for MTP inhibitors were used to direct the synthesis of a highly potent MTP inhibitor. This molecule (compound 9) inhibited the production of lipoprotein particles in rodent models and normalized plasma lipoprotein levels in Watanabe-heritable hyperlipidemic (WHHL) rabbits, which are a model for human homozygous familial hypercholesterolemia. These results suggest that compound 9, or derivatives thereof, has potential applications for the therapeutic lowering of atherogenic lipoprotein levels in humans.

High-risk obstetric patients. Maternal morbidity after cesareans

OBJECTIVE

To assess maternal morbidity associated with cesarean delivery among high-risk obstetric patients in a private practice setting.

STUDY DESIGN

Maternal outcome parameters were prospectively studied in 1,000 consecutively delivered patients over a one-year period.

RESULTS

Three hundred forty-one patients (34%) delivered by cesarean; 194 of the procedures were performed without labor. The incidence of febrile morbidity and wound infection in patients undergoing cesarean delivery without labor, 0.5%, was no greater than that of patients who delivered vaginally (P = 1.0). There was a higher incidence of transfusion in patients delivered by cesarean without labor, but these patients were more likely to have preoperative anemia (P = .036). Patients undergoing cesarean with labor or ruptured membranes had an increased incidence of both febrile morbidity (P = .023) and wound seroma (P = .008).

CONCLUSION

Maternal morbidity following cesarean delivery in high-risk obstetric patients in a private practice setting is low.

Improving productivity in the dental practice: a starting point

Materials, patients, and information flow through the business, but all must pass through the dentist's hands. Thus they are the constraint within the dental practice. Dentists therefore must pay close attention to streamlining and simplifying clinical processes, delegating administration wherever possible, and outsourcing technical services. It is recommended that techniques such as four-handed dentistry, tray-batching of instruments, computerisation of records, and efficient scheduling of appointments, be adopted to improve through-put. Measures used to assess decision-making and performance-evaluation include the use of a computerised cashbook, appointment-book analysis, comparison of actual versus budgeted income and expenditure, net profit, and return on investment. These measurements are, however, an adjunct to intuition and experience. There must be an awareness that, if patient perceptions fall short of their expectations because of the improvement in clinical efficiencies, such optimisation would be to the detriment of the practice. To achieve on-going improvement, the dentist must create a learning environment where motivated team members are willing to engage in systematic problem solving, experimentation, and the learning and transfer of knowledge.

Establishing a competitive advantage through quality management

The successful dentist of the future will establish a sustainable competitive advantage in the marketplace by recognising that patients undergoing dental treatment cannot see the result before purchase, and that they therefore look for signs of service quality to reduce uncertainty. Thus the successful dentist will implement a quality programme that recognises not only that quality is defined by meeting patients' needs and expectations, but also that quality service is fundamental to successful business strategy. Finally, the successful dentist of the future will realise that the pursuit of quality is a never-ending process which requires leadership by example.

Important characteristics of a director of medical education

In osteopathic graduate medical education programs, the Director of Medical Education (DME) plays the key leadership role. This article outlines critical characteristics and skills that the DME should possess to successfully perform in this role. Central to this success is a passionate commitment to osteopathic medical education and a commitment to justice and fairness.

Developmental expression of the platelet-derived growth factor alpha-receptor gene in mammalian central nervous system

We recently reported that the platelet-derived growth factor (PDGF) A-chain gene is highly expressed in neurons of embryonic and adult mouse central nervous system and suggested that its secretion by neurons may support development and maintenance of glia. We have now analyzed the levels and sites of expression of the cognate PDGF alpha-receptor gene in brain and spinal cord of embryonic and adult mice by in situ hybridization. The predominant cell populations in both gray and white matter expressing transcripts of the PDGF alpha-receptor gene are glial cells or their precursors. Transcripts consistently were not detected in neurons. Expression of the PDGF alpha-receptor gene was first observed at embryonic day 15, increased through postnatal day 14, and fell to lower levels in adults. Expression of the alpha-receptor gene corresponds in temporal sequence to the developmental period of glial migration and proliferation and to the expression of PDGF A by neurons. The results indicate that glia but not neurons have the potential to respond to PDGF A and suggest that neurons influence glial cell development through paracrine regulation.

HIV encephalopathy presenting as hypomania

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Amphotericin B lipid complex therapy of experimental fungal infections in mice

The amphotericin B lipid complex (ABLC), which is composed of amphotericin B and the phospholipids dimyristoyl phosphatidylcholine and dimyristoyl phosphatidylglycerol, was evaluated for its acute toxicity in mice and for its efficacy in mice infected with a variety of fungal pathogens. ABLC was markedly less toxic to mice when it was administered intravenously; it had a 50% lethal dose of greater than 40 mg/kg compared with a 50% lethal dose of 3 mg/kg for Fungizone, the desoxycholate form of amphotericin B. ABLC was efficacious against systemic infections in mice caused by Candida albicans, Candida species other than C. albicans, Cryptococcus neoformans, and Histoplasma capsulatum. ABLC was also efficacious in immunocompromised animals infected with C. albicans, Aspergillus fumigatus, and H. capsulatum. Against some infections, the efficacy of ABLC was comparable to that of Fungizone, while against other infections Fungizone was two- to fourfold more effective than ABLC. Against several infections. Fungizone could not be given at therapeutic levels because of intravenous toxicity. ABLC, with its reduced toxicity, could be administered at drug levels capable of giving a therapeutic response. ABLC should be of value in the treatment of severe fungal infections in humans.

Complications of treatment for cryptosporidial diarrhoea

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Preliminary characterization of phosphotyrosine phosphatase activities in human peripheral blood lymphocytes: identification of CD45 as a phosphotyrosine phosphatase

A preliminary characterization of the protein phosphotyrosine phosphatase (PTPase) activity in human peripheral blood lymphocytes (PBL) has been made using two tyrosine-containing peptides and the epidermal growth factor receptor from A-431 cells as substrates. High PTPase activity with a pH optimum near 7.4 was observed in both the membrane and the cytosolic fractions. At least three distinct fractions with PTPase activity were separated on DEAE cellulose columns, indicating that the enzyme is heterogeneous. Vanadate, molybdate, and salts of zinc, copper, and mercury were all effective enzyme inhibitors, although the inhibition was generally incomplete and showed some variation with the enzyme preparation. The difficulty in completely inhibiting PTPase activity in lymphocytes may help explain the variation between laboratories in studies of tyrosine phosphorylation in these cells. Studies with highly purified T lymphocytes obtained by filtration of PBL through nylon wool columns indicated that the activity is present in T cells. Absorption with agarose containing anti-HLe-1, a mouse monoclonal IgG1 antibody specific for the leukocyte-specific surface protein T-200 (CD45), removed up to 40% of the PTPase activity. Enzyme activity was recovered on the immunoadsorbent after extensive washing, confirming that the enzyme was being bound to the beads. Immunoabsorbents containing other mouse IgG1 antibodies failed to bind PTPase activity, indicating that the binding to beads with anti-HLe-1 antibody is specific. Further characterization of the CD45 and PTPase activities in lymphocytes may provide a better understanding of the role of protein tyrosine phosphorylation in the regulation of proliferation and differentiation in these cells.

In vitro phosphorylation of bovine adrenal chromaffin cell tyrosine hydroxylase by endogenous protein kinases

Under phosphorylating conditions, addition of Ca2+ or cyclic AMP to the 100,000 g supernatant of purified bovine adrenal chromaffin cells increases both the incorporation of 32P into tyrosine hydroxylase and the activity of the enzyme. Combining maximally effective concentrations of each of these stimulating agents produces an additive increase in both the level of 32P incorporation into tyrosine hydroxylase and the degree of activation of the enzyme. The increased phosphorylation by Ca2+ is due to stimulation of endogenous Ca2+-dependent protein kinase activity and not inhibition of phosphoprotein phosphatases. When the chromaffin cell supernatant is subjected to diethylaminoethyl (DEAE) chromatography to remove calmodulin and phospholipids, tyrosine hydroxylase is no longer phosphorylated or activated by Ca2+; on the other hand, phosphorylation and activation of tyrosine hydroxylase by cyclic AMP are not affected. Subsequent replacement of either Ca2+ plus calmodulin or Ca2+ plus phosphatidylserine to the DEAE-fractionated cell supernatant restores the phosphorylation, but not activation of the enzyme. Reverse-phase HPLC peptide mapping of tryptic digests of tyrosine hydroxylase from the 100,000 g supernatant shows that the Ca2+-dependent phosphorylation occurs on three phosphopeptides, whereas the cyclic AMP-dependent phosphorylation occurs on one of these peptides. In the DEAE preparation, either cyclic AMP alone or Ca2+ in the presence of phosphatidylserine stimulates the phosphorylation of only a single phosphopeptide peak, the same peptide phosphorylated by cyclic AMP in the crude supernatant. In contrast, Ca2+ in the presence of calmodulin stimulates the phosphorylation of three peptides having reverse-phase HPLC retention times that are identical to peptides phosphorylated by Ca2+ addition to the crude unfractionated 100,000 g supernatant. Rechromatography of the peaks from each of the in vitro phosphorylations, either in combination with each other or in combination with each of the seven peaks generated from phosphorylation of tyrosine hydroxylase in situ, established that cyclic AMP, Ca2+/phosphatidylserine, and Ca2+/calmodulin all stimulate the phosphorylation of the same reverse-phase HPLC peptide: in situ peptide 6. Ca2+/calmodulin stimulates the phosphorylation of in situ peptides 3 and 5 as well. Thus, tyrosine hydroxylase can be phosphorylated in vitro by protein kinases endogenous to the chromaffin cell. Phosphorylation occurs on a maximum of three of the seven in situ phosphorylated sites, and all three of these sites can be phosphorylated by a Ca2+/calmodulin-dependent protein kinase.

High frequency oscillations and mucociliary transport

Mucociliary transport is influenced by high frequency oscillation of air within the lungs. While some studies suggest that high frequency ventilation may be detrimental, with appropriate techniques, there is no doubt that this has potential as a means of improving the clearance of secretions from the lung.

Supplemental oxygen and exercise ability in chronic obstructive airways disease

The influence of supplemental oxygen on exercise performance was assessed in 17 patients with severe airflow obstruction. Exercise capacity was measured by the six minute walking distance, by an endurance walking test, and by an endurance cycling test and comparison was made with performance when the patient was breathing air. In addition, the relation between the flow rate of supplemental oxygen and cycling endurance time was studied. Portable oxygen (41 min-1) carried by the patient increased the mean endurance walking time by 59% and the six minute walking distance by 17%. The endurance time for cycling at a constant work load was increased by 51% with oxygen at a flow rate of 21 min-1, by 88% at 41 min-1, and by 80% at 61 min-1. Supplemental oxygen prolonged the length of time that the patients were able to walk at a fixed speed. It also increased the mean speed achieved during a six minute walk but this was variable and did not occur in all the subjects. The benefit from supplemental oxygen was not cancelled by the effort of carrying the portable cylinder.

Aerosol deposition in the human lung: effect of high-frequency oscillation on the deposition characteristics of an inhaled nebulized aerosol

1. Oral high-frequency oscillation (OHFO) may have important effects on aerosol deposition in the lungs. In order to investigate these, a technique was devised to measure regional deposition rates of a nebulized radiolabelled aerosol in the lungs during normal tidal breathing. 2. The effect of three frequencies of OHFO on pulmonary aerosol deposition rate (PADR) in four normal subjects and five patients with chronic airways obstruction (CAO) were assessed using the technique. 3. In separate experiments employing three normal subjects, the effect of OHFO was studied on the deposition rate of aerosol on the oropharynx and delivery apparatus, and on the amount and characteristics of aerosol inhaled by the subjects. 4. Total PADR was significantly reduced by OHFO at 8 Hz and 16 Hz in the normal subjects, and by all three frequencies of OHFO in the CAO patients. In the normal subjects, the regional distribution of aerosol deposition was unchanged, but in the CAO patients a larger proportion of total aerosol deposition occurred in peripheral lung. 5. OHFO reduced the oropharyngeal aerosol deposition rate, increased the loss of aerosol to the atmosphere before inhalation, and increased the deposition of aerosol on the delivery apparatus. The end result was a reduction in the amount of aerosol inhaled, and in the particle sizes measured at the mouthpiece. 6. We conclude that OHFO reduces the amount of aerosol inhaled, but may improve peripheral deposition of inhaled aerosol in patients with CAO. This effect may be of value in the clinical administration of nebulized drugs.

Thoracoscopy: assessment of a physician service and comparison of a flexible bronchoscope used as a thoracoscope with a rigid thoracoscope

The practicality of physicians performing thoracoscopy for diagnostic purposes was assessed in 30 patients with pleural effusions of unknown cause. A rigid thoracoscope was compared with a fibreoptic bronchoscope used as a flexible thoracoscope and the diagnostic adequacy of biopsy specimens obtained with the two instruments assessed. The two instruments were inserted by a physician in the bronchoscopy suite using local anaesthesia. The procedure proved safe, acceptable, and diagnostically effective. The rigid thoracoscope proved a more satisfactory instrument but the fibreoptic bronchoscope, with minor adaptations, may be used for thoracoscopy.

An oxygen conserving nasal cannula

Oxygen administration via a nasal cannula incorporating a small collapsible reservoir (Oxymizer, Chad Therapeutics Inc, California) was compared with delivery via a standard nasal cannula. Twelve patients with chronic, stable hypoxaemia (arterial oxygen tension less than 60 mm Hg (8.0 kPa)) were studied. Transcutaneous oxygen and carbon dioxide tensions were recorded by skin electrodes and oxygen saturation by ear oximetry. Baseline measurements during the breathing of air were compared with those made during the breathing of oxygen at flow rates of 0.5, 1.0, and 2.0 l/min via each device. Increases in saturation and transcutaneous oxygen tension were significantly greater at each flow rate with the reservoir device than with the conventional cannula. To produce similar improvements in oxygenation the reservoir device required an oxygen flow rate about half that of the conventional cannula. Use of the reservoir device may reduce the inconvenience and perhaps the cost of supplying domiciliary oxygen, and prolong the time during which patients may rely on a portable cylinder.

Effect of oral high frequency ventilation by jet or oscillator on minute ventilation in normal subjects

Normal subjects were asked to breathe through an open ended tube while high frequency oscillations were superimposed on tidal breathing via a side arm, either an eight inch (20 cm) loudspeaker or a jet ventilator being used. Both systems were comfortable and well tolerated. Spontaneous minute ventilation fell by 19-46% at frequencies up to 33 Hz without a rise in transcutaneous PCO2. Maximum ventilatory savings occurred at 1.6 Hz with the jet ventilator (p less than 0.01) and at a frequency corresponding to respiratory system resonance with the loudspeaker. This suggests that during oral high frequency ventilation pulmonary gas exchange is improved and leads to more efficient carbon dioxide excretion for a given minute ventilation. This technique provides a practical and simple method of supplementing breathing in conscious subjects, and it may also have application in the management of patients with acute or chronic respiratory failure, where intubation and conventional ventilation might be avoided.

Ventilatory saving by external chest wall compression or oral high-frequency oscillation in normal subjects and those with chronic airflow obstruction

Oscillation of the air within the lungs at high frequency is associated with an increased clearance of CO2. Because of the high frequency and low volume of these oscillations, spontaneous breathing is unhindered and the technique has potential value as a supplement to ventilation. High-frequency oscillations were superimposed upon tidal breathing by using a loudspeaker attached to a mouthpiece (oral high-frequency oscillation, OHFO) or by external chest wall compression (ECWC). We set out (a) to compare the changes in ventilation and breathlessness by using OHFO and ECWC in normal subjects with those in patients with chronic airflow obstruction (CAO), and (b) to relate the pattern of saving to the resonant frequencies of the respiratory system as a whole (for, 5-10 Hz in normal subjects, 16-26 Hz in CAO) and those of the ribcage (foc, 70 Hz). OHFO reduced minute ventilation (VE) by up to 46% in normal subjects (P less than 0.01) and 29% in CAO (P less than 0.01) without any rise in CO2. ECWC reduced VE by 27% in normal subjects (P less than 0.01) and 16% in CAO (P less than 0.01) without a rise in CO2. High-frequency oscillation by either method relieved breathlessness in those with CAO and was comfortable and well tolerated. In normal subjects for was discrete and varied little with respiration. Maximum savings occurred around for (5-10 Hz). In CAO, there was no obvious single resonant frequency and flow and pressure signals were intermittently in phase over a band of about 10 Hz. Thus the reductions in minute ventilation were only loosely related to for (13-26 Hz). Neither group reduced VE at foc (65-75 Hz). OHFO has considerable potential in the management of patients with CAO, where it may be of value as an assistance to breathing and in the relief of breathlessness. ECWC, although effective in principle, is impractical by our methods and awaits the development of an acceptable delivery system.

Duodenal perforation associated with tolazoline

A neonate, managed with tolazoline for pulmonary hypertension after repair of a congenital diaphragmatic hernia, developed a duodenal perforation. The role of tolazoline in this condition is discussed, and possible measures to reduce its gastrointestinal side effects are proposed.

Increase in mucociliary clearance in normal man induced by oral high frequency oscillation

Data on the effect on mucociliary clearance of oral high frequency oscillation is conflicting. By means of a technique to superimpose high frequency oscillation on tidal breathing, changes in mucociliary clearance during high frequency oscillation were studied in seven normal non-smokers by monitoring the clearance of inhaled radiolabelled aerosol from the lungs. After inhalation of 5 microns technetium 99m labelled particles under controlled conditions, whole lung clearance was monitored by scintillation counters half hourly for six hours with a final count at 24 hours, from which tracheobronchial deposition and clearance could be calculated. Control and high frequency oscillation studies were performed on separate days in random order. Oral high frequency oscillation was applied by a bass loudspeaker through a mouthpiece to superimpose sinewave oscillations (RMS input pressure 1.2 cm H2O, mean pressure zero) on normal breaths. On high frequency oscillation days 30 minutes of oscillation alternated with 30 min of rest. Between 3 and 4.5 hours mucociliary clearance with high frequency oscillation exceeded control by about 10% (p less than 0.05). The mean time taken to eliminate 90% of deposited radioaerosol from the tracheobronchial tree fell from 4 hours 50 minutes (range 1 h 52 min-6 h 50 min) during control to 3 hours 43 minutes (range 2 hr 28 min-5 hr 54 min) during the high frequency oscillation run (p less than 0.05). Possibly this comfortable, simple technique would be of therapeutic benefit to patients with chronic sputum retention and merits further investigation.

High frequency ventilation

What is high frequency ventilation? Is it useful or just another transatlantic fad? Apart from appearing to break all the rules of physiology, this technique has definite advantages over conventional ventilation in certain areas and great potential in others.

The effects of theophylline and salbutamol on right and left ventricular function in chronic bronchitis and emphysema

We have compared the effects of oral theophylline and salbutamol on right and left ventricular function in twelve patients with chronic bronchitis and emphysema. Right and left ventricular ejection fraction (RVEF and LVEF) were measured using multiple gated radionuclide ventriculography. Theophylline 600 mg and salbutamol 4 mg both produced increases in RVEF and LVEF. There were no significant changes in blood gases after either drug. The clinical significance of the effects of oral bronchodilators on cardiac function in patients with chronic bronchitis and emphysema has yet to be determined.

High frequency oscillations improve nasal mucociliary transport

The saccharin clearance time technique was used to determine the effect upon nasal mucociliary transport of sine wave oscillations. Nasal air was oscillated at 8 Hz, 14 Hz, and 20 Hz by a loudspeaker attached to a nasal mask. Mucociliary transport was significantly increased at all frequencies with an overall mean rise of 161%. Because sine waves have zero mean pressure and flow, the improvement is more likely to be caused by changes in mucus viscoelasticity or ciliary function rather than by a direct physical effect on mucus velocity. This simple and comfortable technique may have practical application in patients with overproduction or retention of mucus within the nasal passages or intrathoracic airways.

Self-administered home intravenous antibiotic therapy in bronchiectasis and adult cystic fibrosis

10 patients (mean age 23.1, range 17.1-40.5 years), 8 with cystic fibrosis (CF), and 2 with advanced bronchiectasis without CF, were taught, while being treated in hospital for exacerbations of pseudomonas infection, how to continue to give themselves intravenous antibiotics at home. They were discharged after satisfactory antibiotic levels had been achieved, and 22 courses were given at home over a total of 116 patient-days. In 14 of these, the greater part of the course was given at home (mean duration 6.6, range 5-10 days); 2 of these were given without admission to hospital. In the 8 patients with two or more infective exacerbations within a 12-month period there was no difference between home and hospital treatments in clinical improvement or in relapse time, defined as the interval between completion of treatment and subsequent antibiotic therapy. Self-administration of antibiotics intravenously at home for selected adults with cystic fibrosis and severe bronchiectasis reduces hospital stay and does not seem to be associated with an increased rate of recurrent infection.

Pretreatment extraperitoneal surgical staging in primary carcinoma of the cervix uteri

Sixty-one patients with invasive carcinoma of the cervix uteri underwent extraperitoneal pelvic and para-aortic lymph node sampling along with the exploratory laparotomy. Using the adverse surgical effects criteria modified from the G.O.G., the clinical course of this group of patients was analyzed, retrospectively. The demonstration of metastases had an adverse effect upon survival whether the metastatic disease occurred in the para-aortic or pelvic node regions. No substantial delay in the initiation of radiotherapy occurred regardless of the severity of toxicity.

Multiple site phosphorylation of tyrosine hydroxylase. Differential regulation in situ by a 8-bromo-cAMP and acetylcholine

Suspension cultures of purified bovine adrenal chromaffin cells incorporated 32P from exogenous 32Pi into a protein of approximately M4 = 60,000 (isolated by discontinuous, sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis). Phosphorylated tyrosine hydroxylase, purified from chromaffin cell supernatants by immunoprecipitation, co-migrated with the Mr = 60,000 band. Tryptic fragments prepared fom either the Mr congruent to 60,000 band or the immunoprecipitated tyrosine hydroxylase band were analyzed after separation with two-dimensional electrophoresis/chromatography. Two distinct 32P-peptides were present in either sample. After a 2-3-min lag period. 32P incorporation into both peptides was relatively linear with time for at least 20 min. In the presence of calcium, exogenous acetylcholine (100 microM) increased 32P incorporation into both of the 32P-labeled tryptic peptides whereas 8-bromo-cAMP (1 mM) increased 32P incorporation into only one of the two. Ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid and MnCl2 inhibited the acetylcholine-induced phosphorylation of both tryptic peptides. Thus, tyrosine hydroxylase is phosphorylated in situ at more than one site, and the phosphorylation of these sites is affected differently by acetylcholine and 8-bromo-cAMP. The data imply that kinase activity other than (or in addition to) cAMP-dependent protein kinase activity attends tyrosine hydroxylase in the intact chromaffin cells and that multiple kinase activities may be involved in the short term regulation of catecholamine biosynthesis by afferent activity.

Acute right heart failure complicated by hypovolaemia

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