Oral absorption of peptides and nanoparticles across the human intestine: Opportunities, limitations and studies in human tissues.

In this contribution, we review the molecular and physiological barriers to oral delivery of peptides and nanoparticles. We discuss the opportunities and predictivity of various in vitro systems with special emphasis on human intestine in Ussing chambers. First, the molecular constraints to peptide absorption are discussed. Then the physiological barriers to peptide delivery are examined. These include the gastric and intestinal environment, the mucus barrier, tight junctions between epithelial cells, the enterocytes of the intestinal epithelium, and the subepithelial tissue. Recent data from human proteome studies are used to provide information about the protein expression profiles of the different physiological barriers to peptide and nanoparticle absorption. Strategies that have been employed to increase peptide absorption across each of the barriers are discussed. Special consideration is given to attempts at utilizing endogenous transcytotic pathways. To reliably translate in vitro data on peptide or nanoparticle permeability to the in vivo situation in a human subject, the in vitro experimental system needs to realistically capture the central aspects of the mentioned barriers. Therefore, characteristics of common in vitro cell culture systems are discussed and compared to those of human intestinal tissues. Attempts to use the cell and tissue models for in vitro-in vivo extrapolation are reviewed.

Transitory derepression and the maintenance of conjugative plasmids.

It has been proposed that bacterial plasmids cannot be maintained by infectious transfer alone and that their persistence requires positive selection for plasmid-borne genes. To test this hypothesis, the population dynamics of two laboratory and five naturally occurring conjugative plasmids were examined in chemostat cultures of E. coli K-12. Both laboratory plasmids and three of the five wild plasmids failed to increase in frequency when introduced at low frequencies. However, two of the naturally occurring plasmids rapidly increased in frequency, and bacteria carrying them achieved dominance in the absence of selection for known plasmid-borne genes. Three hypotheses for the invasion and persistence of these two plasmids were examined. It is concluded that although these two extrachromosomal genetic elements are repressed for conjugative pili synthesis, as a consequence of high rates of transfer during periods of transitory derepression in newly formed transconjugants, they become established and are maintained by infectious transfer alone. The implications of these observations to the theory of plasmid maintenance and the evolution of repressible conjugative pili synthesis are discussed.

Phosphate and calcium uptake by rat odontoblast-like MRPC-1 cells concomitant with mineralization.

It has been suggested that odontoblasts are instrumental in translocating Ca2+ and inorganic phosphate (Pi) ions during the mineralization of dentin. The aim of this study was to characterize cellular Pi and Ca2+ uptake in the novel rat odontoblast-like cell line mineralizing rat pulpal cell line (MRPC) 1 during mineralization to see if changes in the ion transport activity would occur as the cultures develop and begin forming a mineralized matrix. MRPC-1 cells were cultured in chemically defined medium containing ascorbate and Pi, and cultures were specifically analyzed for cellular P, and Ca2+ uptake activities and expression of type II high-capacity Na+-Pi cotransporters. The odontoblast-like phenotype of the cell line was ascertained by monitoring the expression of collagen type I and dentin phosphopoprotein (DPP). Mineralized nodule formation started at day 9 after confluency and then rapidly increased. Ca2+ uptake by the cells showed a maximum during the end of the proliferative phase (days 5-7). Pi uptake declined to a basal level during proliferation and then was up-regulated simultaneously with the onset of mineralization to a level fourfold of the basal uptake, suggesting an initiating and regulatory role for cellular Pi uptake in mineral formation. This up-regulation coincided with a conspicuously increased glycosylation of NaPi-2a, indicating an activation of this Na+-Pi cotransporter. The study showed that MRPC-1 cells express an odontoblast-like phenotype already at the onset of culture, but that to mineralize the collagenous extracellular matrix (ECM) that formed, a further differentiation involving their ion transporters is necessary.

Methotrexate and 5-fluorouracil in head and neck cancer.

Since experimental data strongly suggest a synergistic cytotoxic effect when methotrexate (MTX) and 5-fluorouracil (5-FU) are administered sequentially, we investigated antitumor effects and toxicity with sequential MTX/5-FU followed by leucovorin rescue in 52 patients with carcinoma of the head and neck. MTX (200 mg/m2) was given as an i.v. infusion over 1 hr. At 2 hr, 5-FU (600 mg/m2) was started as an i.v. infusion for 2 hr. At 24 hr, the leucovorin rescue was started. The chemotherapy course was repeated every week until toxicity (mainly gastrointestinal) occurred, after which the interval between courses was prolonged to 2 wk. Toxicity was mild and usually disappeared when the interval between the chemotherapy courses was prolonged to 2 wk. The regression rate was 15% for complete and 48% for partial regression (response rate, 63%). In 31 of the patients not previously treated, the objective response rate was 74%. About the same results were obtained for tumors of different anatomic sites of the head and neck. Radiotherapy could be added sequentially without measurable escalation of toxicity. We conclude that sequential MTX/5-FU treatment, which produces a very mild toxicity to normal tissue, is effective in inducing antitumor response in patients with carcinoma of the head and neck.

Regional variation in plasminogen activator inhibitor-1 expression in adipose tissue from obese individuals.

High plasma plasminogen activator inhibitor-1 (PAI-1) activity is a frequent finding in obesity and adipose tissue has recently been suggested to be a source of circulating PAI-1 in humans. In the present study, differences in adipose tissue gene expression and protein secretion rate of PAI-1 between subcutaneous and visceral adipose tissue was analysed in specimens obtained from 22 obese individuals. The secretion rate of PAI-1 was two-fold higher in subcutaneous adipose tissue than in visceral adipose tissue (292 +/- 50 vs 138 +/- 24 ng PAI-1/10(7) cells, P <0.05). In accordance with the secretion data, subcutaneous adipose tissue contained about three-fold higher levels of PAI-1 mRNA than visceral adipose tissue (2.43 +/- 0.37 vs 0.81 +/- 0.12 attomole PAI-1 mRNA/microg total RNA, P <0.00 ). PAI-1 secretion from subcutaneous but not from visceral adipose tissue correlated significantly with cell size (r = 0.43, P<0.05). In summary, subcutaneous adipose tissue secreted greater amounts of PAI-1 and had a higher PAI-1 gene expression than visceral adipose tissue from the same obese individuals. Bearing in mind that subcutaneous adipose tissue is the largest fat depot these finding may be important for the coagulation abnormalities associated with obesity.

Spatial visualization of the maturing HIV-1 core and its linkage to the envelope.

The core of late states of maturing human immunodeficiency virus type 1 (HIV-1) has been visualized in three dimensions at approximately 7 nm resolution by electron microscopic tomography. After budding, approximately 25 nm thick precursor material is observed densely assembled inside the viral envelope. Upon proteolysis the core material is transported and condensed in the center of the virion. The core, 100 nm in length, spans the entire diameter of the virion showing a 40-60 nm wide free end and a narrow end approximately 20 nm. A model of the core is derived consisting of two fibers packed into a bilateral, elongated structure. Two ends of the fibers are compacted together, forming one narrow end of the core, while the two other fiber ends are situated more loosely together allowing for flexibility. Structural maturation of the virus could be reflected by the degree of compactness of the core. The narrow end of the core is observed attached to the envelope with a conspicuous core-envelope link (CEL).

A simple method for determination of plasma thiocyanate.

We describe a method for the determination of thiocyanate in plasma from blood collected under field conditions in heparinised glass capillary tubes. After deproteinisation of plasma with perchloric acid, thiocyanate is directly determined colorimetrically by the König reaction with sodium hypochlorite as the chlorinating reagent and barbituric acid as the coupling agent. This simple method cannot be applied to urine as the latter contains interfering compounds.

Combined preoperative radiotherapy and surgery in the treatment of carcinoma of the anterior two-thirds of the tongue.

Sixty-three patients with squamous cell carcinoma of the anterior two-thirds of the tongue were treated with preoperative external radiotherapy (mean target dose 42.60 Gray or 4260 rad) and surgery. The expected 5-year survival, expressed as life table estimate of percent of survivors, was 77% for patients with Stage I tumors, 69% with Stage II, and 13% for patients with tumors in Stages III-IV (p less than 0.001). Fourteen patients experienced local recurrences, 7 had homolateral neck metastases, 4 had contralateral neck metastases and 3 had distant metastases. In 15 cases no cancer could be detected at review of the surgical specimens, but 2 of these died of their cancers. In 43 cases cancer was present in the specimens, and 26 of these died of their cancer (p less than 0.01).

The role of hydrogen cyanide and carbon monoxide in fire casualties: a prospective study.

Determinations of blood cyanide and carboxyhemoglobin concentrations were performed in 18 victims found dead in buildings after fires during a 2-year period. The results indicated that 50% of the victims had been exposed to toxic levels of hydrogen cyanide and 90% to toxic levels of carbon monoxide. Lethal concentrations of carbon monoxide were found in 83% of the victims. In one case a lethal blood cyanide but a non-toxic blood carboxyhemoglobin value was found. It is concluded that carbon monoxide appears to be more important than hydrogen cyanide as a toxic agent in the fire atmosphere, but cyanide poisoning without carbon monoxide poisoning may, under certain circumstances, be the cause of death in fire victims.

Interferon therapy in juvenile laryngeal papillomatosis.

Seventeen patients with severe juvenile laryngeal papillomatosis (12 in Stockholm and five in Umeå) were treated with exogenous leukocyte interferon (IFN-alpha) prepared in Helsinki and Umeå, respectively. Tumor progression occurred in all cases before treatment. During treatment tumor growth diminished in all cases, up to complete tumor disappearance. Of 17 patients, nine were cured and no longer are being treated, four exhibit no tumor growth but are still being treated, one has visible tumor but only slight growth, two still have active but diminished growth, and one, who has refused further treatment, is experiencing active tumor growth as before the start of interferon therapy. It is concluded that IFN-alpha therapy in a dosage of 3 X 10(6) units three times a week intramuscularly can arrest papilloma growth. Further trials are needed to optimize treatment.

Destruction and regeneration of jawbone after cryogenic application. An experimental study.

On 13 rabbits part of the lateral aspect of the jawbone was frozen with liquid nitrogen in two sessions. The animals were sacrificed 2, 4, 12 and 24 weeks after the cryosurgery. The specimens were analyzed with microangiography according to the Spalteholz technique and with light microscopy. The whole width of the lateral cortex, measuring around 3 mm, was subject to bone destruction two weeks after cryosurgery. New bone formation, on the other hand, was evident in the frozen area and on the undamaged periosteum some distance from the lesion. The same area, 12 weeks after the injury, was completely restored. Bone destruction and regeneration are discussed with special reference to the vascular response to the injury.

Diffuse reflectance spectroscopy of the human tympanic membrane in otitis media.

We have investigated if features in the diffuse reflectance spectra from in vivo spectroscopic measurements of the tympanic membrane could aid the diagnosis of otitis media in children. Diffuse reflectance spectroscopy, in the visible wavelength range, was used in 15 ears from children with otitis media with effusion before and after myringotomy and in 15 healthy ears as a reference. Two previously published erythema detection algorithms yielded numerical quantities of haemoglobin content. With a combination of the algorithms, induced erythema (after myringotomy) was distinguished from healthy ears using Student's t-test (p < 0.01). Otitis media with mucous effusion was distinguished from (1) otitis media with serous effusion, (2) induced erythema and (3) healthy ears, (p < 0.05) using Student's t-test for independent groups and the paired t-test for dependent groups. Our results imply that reflectance spectroscopy is a promising technique to be used for the diagnosis of otitis media.

Essential dataset for ambulatory ear, nose, and throat care in general practice: an aid for quality assessment.

OBJECTIVE: To describe the documentation of care for the usual range of ear, nose, and throat (ENT) problems seen in primary care as a basis for developing a computerised information system to aid quality assessment. DESIGN: Descriptive study of the pattern of ENT problems and diagnoses and treatment as recorded in individual case notes. SETTING: The primary health care centre in Mjölby, Sweden. PATIENTS: Consultations for ENT problems from a 10% sample randomly selected from all consultations (n = 22,600) in one year. From this sample 375 consultations for ENT problems (16% of all consultations) by 272 patients were identified. MAIN MEASURES: The detailed documentation of each consultation was retrieved from the individual records and compared with the data required for a computer based information system designed to help in quality management. RESULTS: Although the overall picture gained from the data retrieved from the notes suggested that ENT care was probably adequate, the recorded details were limited. The written case notes were insufficient when compared with the details required for a computerised system based on an essential dataset designed to allow assessment of diagnostic accuracy and appropriateness of treatment of ENT problems in primary care. CONCLUSION: There is a gap between the amount and the type of information needed for accurate and useful quality assessment and that which is normally included in case notes. More detailed information is needed if general practitioners' notes are to be used for regular quality assessment of ENT problems but that would mean more time spent on keeping notes. This would be difficult to justify. IMPLICATIONS: The routine information systems used at this primary healthcare centre did not produce sufficient documentation for quality assessment of ENT care. This dilemma might be resolved by specially designed desktop computer software accessed through an essential dataset.

Experiments on cochlear cryosurgery in the guinea pig. Light and surface microscopy.

The present investigation indicates that with cryosurgery it is possible to produce well defined cochlear lesions. The point of complete ablation can be chosen at will. A great advantage also is the fact that the bony capsule of the labyrinth is left intact. The remarkably slight scarring caused as well as the morphologically intact walls of the cochlear duct indicate an effective healing process, already completed after 6 days. These findings explain the unsuccessful clinical experiences when trying to ablate the labyrinth completely or to induce labyrinthine fistula with the help of cryosurgery (House, 1966). We suggest that for studies on cochlear function after exogenic trauma, cryosurgery gives easy reproductive morphological changes that may help the understanding and correlation of hair cell loss with cochlear physiology.

Morphological changes in salivary glands after treatment with sialagogues. An electronmicroscopical study.

A dual innervation in salivary glands has been discussed. It is unclear how alpha-adrenergic and cholinergic agents stimulate the secretory cells. Different effects on serous and mucous cells are reported after stimulating with carbachol, clonidine, noradrenaline, cyclocytidine and pilocarpine, respectively. In the rat, carbachol and clonidine predominantly affect the mucous cells, however, with different morphological effects. Cyclocytidine exclusively degranulates the serous cells. Noradrenaline stimulates both serous and mucous cells and gives rise to vast cytoplasmic changes. Pilocarpine only shows effect on the mucous cells with formation of intracytoplasmic vacuoles. The effects reported are discussed with regard to experiments on salivary gland radiosensitivity.

Effects of cryosurgery on the healing pattern of rabbit mandibular bone. A triple fluorochrome labelling study.

The reparative process of rabbit mandibular bone injured by cryosurgery was studied by a triple fluorochromic method. The regeneration started late, when compared with fracture healing, and reached its maximum some 4-8 weeks after cryosurgery. A normal distribution of fluorochromes was registered after l2 weeks. The regeneration occurred mainly through growth from the marrow cavity region where the cryogenic impact may have stimulated osteogenesis from surviving endosteum and bone marrow. The destroyed periosteum at the site of the probe-tip attachment did not regenerate, although new bone formation of periosteal origin was noticed at the border of the injured cortex. The general distribution of fluorochromes seemed to follow closely the autoradiographic image obtained using 99TcmMDP in a similar experiment, suggesting comparable ways of accumulation in bone tissue.

Ultrastructural features of human juvenile laryngeal papillomas.

The ultrastructural organization of 12 juvenile laryngeal papillomas was investigated. Four patients were more than 40 years old but had carried the disease since childhood. The other 8 patients were 2-10 years old and had carried the disease from 1-5 years. There is regularly observed a discontinuity of the basement membrane and the basal cells of ten exhibit abundant cytoplasmic processes. In the stratum spinosum there is often found glycogen-like inclusions as well as Odland bodies and keratohyalin granules. In the superficial layers there are nuclear remnants as in parakeratosis. Virus-like particles of a diameter around 330 A have been demonstrated in a disintegrated superficial cell. The scarcity of such particles is discussed with possible regard to a transformation occurring in the superficial layers of the papilloma and to the high shedding rate of the surface cells.

Ultrasonic irradiation of the guinea pig labyrinth. Correlation of morphology and intralabyrinthine temperature.

The effects of high frequency ultrasound on the inner ear structures after irradiation of the lateral semicircular canal have been analysed by means of light-and electronmicroscopy. Sudden as well as gradual morphological changes in the vestibular sensory epithelium are described. Damage to the connective tissue stroma, blood vessels and nerve fibres characterized the chronic phase. Both cochlear morphology and hearing remained normal after irradiation of some behaviorally conditioned animals. The temperature rise in the labyrinth during continuous irradiation was studied. The experiments indicated that the mechanical effects may be more significant than the thermal in explaining the structural changes of the inner ear of guinea pigs. The results are compared with previous extensive experience of ultrasound treatment of patients with Meniere's disease.

Effects of ligation and irradiation on the submaxillary glands in rats.

Rat submaxillary glands were exposed to excretory duct ligation, high-energy electron irradiation, or a combination of both. Ligation was done on the left excretory ducts, while 24 Gy irradiation was given within 8 days in three divided doses of 8 Gy. In the combined insults, the excretory ducts (one duct per rat) were first ligated, followed by 24 Gy irradiation. The effects were analysed by morphological methods. Ligation of excretory ducts caused morphological disorganization of the gland parenchyma, with resultant disappearance of secretory granules of serous cells, shrinkage of mucous cells, dilation of ducts, pronounced fibrosis and infiltration of inflammatory cells. When irradiated, some serous cells disappeared, leaving empty fibrosed spaces, while mucous cells showed no consequential radio-damage. The combined treatment of ligation of excretory ducts and irradiation caused extensive morphologic evidence of irreversible damage, i.e. no serous cells remained, disfigured and very shrunk mucous cells extremely dilated ducts, infiltration of leukocytes and fibrotic changes of the glands.

Histological grading of malignancy in squamous cell carcinoma of the oral tongue.

A system for histological grading of malignancy was applied to ninety-five squamous cell carcinomas from the anterior 2/3 of the tongue. Three parameters relating to the tumour cell population and three parameters relating to the tumour-host relationship were evaluated. The expected 5-year survival expressed as % survivors was 88% for patients with tumours having total malignancy scores of less than 13 points. 65% for 13-16 and 44% for patients with tumours having scores of more than 16. The prognostic significance for 5-year survival was statistically valid for the three different groups of malignancy scoring. The conventional classification according to mode of differentiation did not give equally good correlations for survival or occurrence of metastases. For the evaluation of the biological behaviour of lingual carcinomas, histological grading of malignancy is a better method.