Cultural and climatic changes shape the evolutionary history of the Uralic languages.

Quantitative phylogenetic methods have been used to study the evolutionary relationships and divergence times of biological species, and recently, these have also been applied to linguistic data to elucidate the evolutionary history of language families. In biology, the factors driving macroevolutionary processes are assumed to be either mainly biotic (the Red Queen model) or mainly abiotic (the Court Jester model) or a combination of both. The applicability of these models is assumed to depend on the temporal and spatial scale observed as biotic factors act on species divergence faster and in smaller spatial scale than the abiotic factors. Here, we used the Uralic language family to investigate whether both 'biotic' interactions (i.e. cultural interactions) and abiotic changes (i.e. climatic fluctuations) are also connected to language diversification. We estimated the times of divergence using Bayesian phylogenetics with a relaxed-clock method and related our results to climatic, historical and archaeological information. Our timing results paralleled the previous linguistic studies but suggested a later divergence of Finno-Ugric, Finnic and Saami languages. Some of the divergences co-occurred with climatic fluctuation and some with cultural interaction and migrations of populations. Thus, we suggest that both 'biotic' and abiotic factors contribute either directly or indirectly to the diversification of languages and that both models can be applied when studying language evolution.

Exogenous sex hormone use and risk of meningioma: a population-based case-control study in Finland.

BACKGROUND: Previous studies on association of exogenous female sex hormones and risk for meningioma have yielded conflicting results. The aim of this study was to evaluate the potential relation between prior use of menopausal hormone therapy or oral contraception and risk of meningioma. METHODS: This population-based case-control study was conducted during years 2000-2002 in Finland. All women aged 20-69 years with meningioma diagnosis were identified from five university hospitals, and frequency-matched controls were randomly chosen from population register. A total of 264 cases and 505 controls were interviewed on their use of menopausal hormone therapy, oral and other contraception, fertility treatment, treatment for gynecological problems, age at menarche, and number of children. We also analyzed separately tumors expressing progesterone or estrogen receptors. Of the successfully stained tumor specimens, 86.3% were positive for progesterone receptor and 50% for estrogen receptor. RESULTS: Postmenopausal hormonal treatment, use of contraceptives, or fertility treatment did not influence the risk of meningioma. In further analysis by hormone receptor status, there was some indication for an increased risk of progesterone receptor-positive meningiomas associated with oral contraceptive use (OR 1.39, 95% confidence interval 0.92-2.10) and other hormonal contraception (OR 1.50, 95% CI 0.95-2.36). CONCLUSIONS: Overall, we found little indication that reproductive factors or use of exogenous sex hormones affect meningioma risk.

Impact of in vitro fertilization of bovine oocytes with sex-sorted frozen-thawed spermatozoa on developmental kinetics, quality and sex ratio of developing embryos.

We studied whether bovine embryos developing after in vitro fertilization (IVF) with sex-sorted spermatozoa differed in developmental kinetics, quality and sex ratio from embryos produced with unsorted spermatozoa. Abattoir-derived oocytes were fertilized with X-sorted, Y-sorted or unsorted spermatozoa from a single bull. To evaluate economical use of the sex-sorted spermatozoa, washed spermatozoa from a single straw (2 million spermatozoa) were used to fertilize each batch of collected oocytes without any further isolation steps. Concentration of the unsorted spermatozoa was adjusted accordingly. Fertilizations were assessed by staining sperm asters at 10 hpi and pronuclei at 20 hpi. Embryo development and morphological quality were monitored on days 2, 7, 8 and 9 of the development (IVF = day 0). All embryos were sexed using PCR. Following fertilization, penetration and subsequent cleavage rates were compromised in the X-sorted group compared with the Y-sorted and unsorted groups (penetration: 58.0% vs. 89.8% and 90.0%, cleavage: 65.3% vs. 81.5% and 75.0%). The use of the sex-sorted spermatozoa did not, however, reduce the proportion of transferable embryos (sex-sorted 29.6% vs. unsorted 27.7%) or their quality (quality 1: sex-sorted 36.0% vs. unsorted 19.9%). The Y-sorted spermatozoa produced more transferable embryos of better quality than the X-sorted spermatozoa (days 7-8: 31.9% vs. 26.4%, quality 1: 38.9% vs. 30.6%). On average, out of 10 transferable embryos, nine were of the predicted sex in the X- and Y-sorted spermatozoa groups. These results indicate that low numbers of X- and Y-sorted spermatozoa can be used successfully for female and male embryo production in vitro.

Effects of serum-free in vitro maturation of bovine oocytes on subsequent embryo development and cell allocation in two developmental stages of day 7 blastocysts.

Maturation of oocytes and the subsequent outcome of the in vitro production (IVP) are affected by the composition of in vitro maturation (IVM) medium. To determine the use of serum interfering with effects of single molecules, we aimed at developing simplified IVM medium. The experimental IVM media were: (1) M199-medium supplemented with hormones and serum (control), (2) as 1 but serum was substituted with fatty acid-free serum albumin (FAFBSA) and (3) M199-medium without hormonal and serum supplementation (M199). The quality of embryos was assessed on day 7 by morphology and cryotolerance, as well as by Terminal deoxynucleotidyl Transferase Biotin-dUTP Nick End Labeling (TUNEL) and differential staining. Results showed that the nuclear maturation was suppressed in M199 group alone. Embryo cleavage and development rates, and the proportion of quality 1 blastocysts were lower in the FAFBSA and M199 groups compared to the control. Differences in the cell allocation of fresh embryos were observed at the blastocyst stage, but not at the expanded blastocyst stage. The control group blastocysts had larger number of cells allocated to the inner cell mass (ICM), and the FAFBSA group blastocysts larger apoptotic cell proportion compared to the blastocysts derived from other groups. After cryopreservation, the reduction of ICM proportion and increase of apoptotic cell proportion of embryos were equal between the experimental groups. In conclusion, exclusion of serum from the IVM media reduces embryo development and may cause perturbations in blastocyst development. Differences in the cell allocation of blastocysts between IVM media may appear only when the developmental stages are taken into account.

A study on intersterility groups of Armillaria in China.

Mating tests were used to identify 282 basidiocarp specimens of Armillaria collected in 15 Chinese provinces, mostly in northern and southwestern parts of the country. Fourteen intersterile taxa were found, including the species A. borealis, A. gallica, A. mellea s.str., A. ostoyae, A. sinapina and A. tabescens and eight so far unnamed taxa called Chinese Biological Species (CBS) C, F, G, H, J, L, N and O. The CBS F might be A. singula, previously recorded from Japan, but six Chinese groups, C, H, J, L, N and O, are probably new biological species. The sexual system of 13 taxa is tetrapolar heterothallism. Homothallic forms also were found; they show a low degree of sexual compatibility with A. mellea s.str. and tentatively are included in the CBS G, but it is unclear whether this is a homogeneous group. Notes are presented on the distribution and ecology of the identified taxa.

Respiratory morbidity 20 years after RSV infection in infancy.

Epidemiological data suggest that respiratory syncytial virus (RSV) infection in early life is a risk factor for later asthma. There are no prospective studies on RSV infection starting from infancy progressing through childhood into adulthood. We followed up a cohort of children, hospitalized for RSV bronchiolitis or RSV pneumonia before age 24 months, until age 18-20 years. The aim of the study was to evaluate early RSV infection as a risk factor for asthma, bronchial reactivity, and lung function abnormalities in young adults. The participants filled in a questionnaire on asthma and asthma-like symptoms. The clinical study included flow-volume spirometry (FVS), methacholine inhalation challenge (MIC), home PEF (peak expiratory flow) monitoring, and skin prick tests (SPT) to common allergens. Asthma was present in 17-22% of 36 index subjects, depending on asthma definition, compared to 11% of 45 controls. Furthermore, FEV% and MEF25 were lower, and MEF50 tended to be lower, in index than in control subjects. One or more abnormal lung function results were found in 16 (44%) index subjects, but only in 5 (11%) controls (P < 0.01). Bronchial reactivity (PD20 <4,900 microg methacholine) was demonstrated in 16 (46%) index subjects and 14 (32%) controls (NS). At least one positive SPT result was present in 21 (60%) index subjects; 6 (29%) had asthma (NS vs. nonatopic index subjects); 13 (62%) had abnormal lung function (P < 0.05); and 14 (67%) had bronchial reactivity (P < 0.01). In the logistic regression adjusted for atopy, as defined by SPT positivity, RSV infection in infancy was an independent risk factor for lung function abnormality (one or more abnormal results in FVS; OR, 5.27; 95% CI, 1.60-17.36), and also for decreased FEV% and MEF50 when these were analyzed separately. However, RSV infection in infancy was not a significant risk factor for asthma or bronchial reactivity. In young adults, lung function abnormalities may be associated with RSV infection which required hospitalization in infancy.

Mechanical ventilation in children with severe asthma.

Hospital admissions for childhood asthma have increased during the past few decades. The aim of this study was to describe the need for mechanical ventilation for severe asthma exacerbation in children in Finland from 1976 to 1995. We reviewed medical records and collected data retrospectively from all 5 university hospitals in Finland, thus covering the entire population of about 5 million. The endpoints selected were the number of admissions and readmissions leading to mechanical ventilation, duration of stay in the hospital, and mortality. Moreover, asthma medications prescribed prior to admission and administered in the intensive care unit (ICU), as well as the etiology of the exacerbation associated with mechanical ventilation were examined. Mechanical ventilation was required in 66 ICU admissions (59 patients). This constituted approximately 10% of all 632 admissions for acute asthma to an ICU. The number of admissions decreased from 1976 to 1995: 41 admissions between 1976 and 1985 vs. 25 admissions during the next 10-year period. The mean age at admission to the ICU was 3.6 years, and 46% of the patients were boys. Prior to the index admission, 70% of the patients had used asthma medication such as oral bronchodilator (50%), inhaled bronchodilator (20%), theophylline (38%), inhaled glucocorticoid (18%), oral glucocorticoid (5%), and cromoglycate (7%). Respiratory infection was by far the most common cause of all the exacerbations (61%), followed by food allergy (8%) and gastroesophageal reflux (3%). In 28% of cases the cause of the severe asthma exacerbation could not be identified. In the mechanically ventilated patients readmissions occurred 38 times between 1976 and 1985 vs. 5 times between 1986 and 1995. Five of the patients who received mechanical ventilation died, and in 3 of these patients asthma was the event causing death. In conclusion, there has been decrease in the number of first and repeat ICU admission for asthma requiring mechanical ventilation between 1970 and 1995. This trend occurred despite a simultaneous 5% yearly increase in hospital admissions for childhood asthma during these 2 decades.

Quantitative radioisotope measurement of duodenogastric reflux in patients with ulcer or gastrectomized for ulcer.

In this work the duodenogastric reflux was quantified as the amount of radioactivity entering the stomach after an i.v. administration of 99mTc-HIDA in ulcer patients and in patients who had undergone BI gastrectomy. The results were compared with visual evidence of gastric activity in the gamma camera images and biochemical determination of gastric bile reflux. The method is useful in quantifying the reflux if the activity is above the background activity. It allows the determination of an upper limit for the reflux when the reflux is evident visually. Only two or three images are needed for the quantitation. No correlation was found between biochemical measurement of fasting bile reflux in the stomach and radioisotopic quantification.

Effect of mast cell chymase of rat skin on intercellular matrix: a histochemical study.

The effects of purified mast cell chymase of rat skin on intercellular matrix were studied histochemically using cartilage as a model. The enzyme effectively releases proteoglycans from neonatal human costal cartilage. An analysis of the primary site of proteolytic attack by chymase in the matrix was attempted. The results suggest that components containing the more acidic radicals (e.g. sulphates) are hydrolyzed first. After a prolonged attack, the matrix loses most of its staining with Toluidine Blue and Alcian Blue, and staining of collagen is increased. The hydrolyzed regions of cartilage in Alcian Blue-stained sections exhibited a purple interference colour in polarized light. A similar interference colour appeared after incubating sections of rat skin with chymase. The mast cell chymase presumably promotes diffusion of plasma to the site of injury by the direct breakdown of connective tissue ground substance.

First Report of Heterobasidion parviporum (S Group of H. annosum sensu lato) on Tsuga spp. in Asia.

Members of the Heterobasidion annosum (Fr.) Bref. complex are among the most important pathogens in coniferous forests of Europe and North America. Three intersterile groups (P, S, and F) have been found in this complex from Europe (1) and were recently segregated into three species based on intersterility, host preferences, and morphology (4). In a survey of wood-rotting fungi in China in 2002, Heterobasidion spp. were found on Tsuga chinensis (Franch.) Pritz and T. dumosa (D. Don) Eichl. in natural forests from the northern Sichuan Province of southwestern China (32°43' to 33°11' N, 103°50' to 103°53' E.). Basidiocarps of the fungus were relatively common on decayed wood in roots of dead trees, stumps, and fallen trunks. We collected four basidiocarps (Dai 4045, 4051, 4214, and 4224 in the Institute of Applied Ecology, Chinese Academy of Sciences, IFP) from three stands of mixed coniferous forests and made 40 homokaryotic, single-basidiospore cultures (02046, 02047, 02050, and 02051 in the Finnish Forest Research Institute). Two homokaryons from each basidiocarp were paired with homokaryotic tester strains of European H. annosum (P group), H. parviporum Niemelä & Korhonen (S group), and H. abietinum Niemelä & Korhonen (F group). The pairings showed that the progeny from the four basidiocarps are H. parviporum. The Chinese isolates did not form clamp connections with H. annosum sensu stricto, and a strong demarcation line developed in all these pairings. In contrast, the Chinese isolates formed clamp connections in almost every pairing with European H. parviporum, the clamp connections developed in both sides of the pairings, and no distinct demarcation line was present in most of these pairings. The Chinese homokaryons were also compatible with European H. abietinum, but in most of these pairings, clamp connections were found in the isolate from China but not in the European tester, and a demarcation line was present in most of the pairings. In contrast to H. annosum sensu stricto, the Chinese basidiocarps had smaller pores (4.5 to 6 per mm versus 3 to 4.5 per mm), and a thin tomentum on the pileal surface in contrast to the basidiocarps of H. abietinum. Previously, H. parviporum was found in Asia on coniferous hosts such as Abies, Larix, Picea and Pinus spp. (2). The North American S group of H. annosum sensu lato attacks species of Tsuga spp. in western North America (3), but to our knowledge, this is the first report of H. parviporum on native species of Tsuga spp. outside North America. References: (1) P. Capretti et al. Eur. J. For. Pathol. 20:231, 1990. (2) Y. C. Dai and K. Korhonen. Eur. J. For. Pathol. 29:273, 1999. (3) G. M. Filip and D. J. Morrison. North America. Pages 405-427 in: Heterobasidion annosum. Biology, Ecology, Impact and Control. CAB International, Wallingford, UK, 1998. (4) T. Niemelä and K. Korhonen. Taxonomy of the genus Heterobasidion. Pages 27-33 in: Heterobasidion annosum. Biology, Ecology, Impact and Control. CAB International, Wallingford, UK, 1998.

Diffusion and perfusion MR imaging in acute ischemic stroke: a comparison to SPECT.

Diffusion (DWI) and perfusion (PWI) magnetic resonance imaging are relatively new methods of clinical imaging that probably can detect infarcted (DWI) and hypoperfused but still salvageable tissue (PWI) in acute human stroke. Forty-six acute stroke patients were imaged within 24 h of ictus, on the second day and after a week. SPECT was also performed on 23 patients in the acute phase (first or second day). On the first day, mean volume of hypoperfused tissue was significantly greater (P<0.001) than the infarcted tissue. The initial hypoperfusion volume correlated significantly with the final infarct size (P<0.001). The initial perfusion-diffusion mismatch correlated significantly with the infarct growth (P< or =0.001). The hypoperfusion volumes measured from PWI and SPECT correlated significantly (P<0.001). In conclusion, combined DWI and PWI is a powerful tool in evaluating the hemodynamics of acute ischemic stroke and can predict the infarct growth during 1 week.

The effect of ascorbic acid during biopsy and cryopreservation on viability of bovine embryos produced in vivo.

Multiple ovulation embryo transfer (MOET) is used to make more rapid progress in animal breeding schemes. On dairy farms, where female calves are more desired, embryo sex diagnosis is often performed before embryo transfer. Fresh transfers have been favored after biopsy due to cumulative drop in pregnancy rates following cryopreservation. The aim of this study was to explore whether exposure to ascorbic acid (AC) during biopsy and freezing increases the viability of biopsied embryos after cryopreservation. Data on presumptive pregnancy and calving rates of biopsied and cryopreserved/overnight-cultured embryos were gathered. Results showed differences in presumptive pregnancy rates between the groups: 45% for both biopsied-cryopreserved groups (control and AC), 51% for biopsied-overnight-cultured embryos and 80% for intact-fresh embryos. Differences between the groups were also apparent in calving rates: 22% for biopsied-cryopreserved control embryos, 31% for biopsied-cryopreserved AC-embryos, 23% for biopsied-overnight-cultured embryos and 63% for intact-fresh embryos. It is concluded that manipulated embryos are associated with lower presumptive pregnancy and calving rates compared with intact-fresh embryos. The highest calving rates for groups of manipulated embryos were achieved in the AC-group. Therefore, addition of AC can be recommended if biopsy is combined with freezing before transfer.

Apparent Diffusion Coefficient Histograms in the Follow-up of Relapsing-Remitting Multiple Sclerosis.

Diffusion-weighted (DW) magnetic resonance (MR) imaging in addition to conventional magnetic resonance MR images provide valuable information in multiple sclerosis (MS). Increased diffusivity measured with diffusion-weighted imaging (DWI) has been demonstrated in normal appearing brain tissue in MS. So far, longitudinal changes taking place in whole-brain histograms in patients with active relapsing-remitting MS have not been evaluated. The aim of this study was to evaluate how apparent diffusion coefficient (ADC) histograms are altered during the follow-up of active relapsing-remitting MS patients. Nine patients were studied twice by MRI with a three-month interval. All patients had active newly diagnosed MS with two to three relapses during the year preceding the first MRI, and interferon-beta treatment was initiated after obtaining the first image. ADC histograms were produced after removing extracranial tissues and cerebrospinal fluid from the images. Additionally, brain volume index (BVI) and lesion volume on FLAIR images were measured. Five patients had signs of disease activity in the follow-up MRI. In the four patients without signs of disease activity the change in ADC histogram parameters was less than 2%. In patients with disease activity both increase (one case) and decrease (four cases) in histogram parameters were detected. Changes in BVI or lesion volume did not significantly correlate with histogram changes. The number of new T2-lesions showed a positive correlation with mean (r=0.79, P=0.014) and upper quartile (r=0.77, P=0.021) value change. Alterations in disease activity lead to histogram changes; both shifts to lower values and shifts to higher values are possible. The histogram changes are mostly related to subtle inflammatory changes in normal appearing brain tissue during inflammatory activity and their resolution during less active inflammatory conditions.

Embryo production from superovulated Holstein-Friesian dairy heifers and cows after insemination with frozen-thawed sex-sorted X spermatozoa or unsorted semen.

The aim of this study was to evaluate embryo production in superovulated Holstein-Friesian dairy heifers and cows inseminated with either X-sorted spermatozoa (2 million/dose) or unsorted semen (15 million/dose). Experiment 1 at the research farm involved eight heifers, six cows and semen of one Holstein bull. All transferable embryos were diagnosed for sex. Experiment 2 included embryo collections on commercial dairy farms: X-sorted spermatozoa from three Holstein bulls were used for 59 collections on 28 farms and unsorted semen from 32 Holstein bulls were used for 179 collections on 79 farms. Superovulations were induced by eight declining doses of FSH (total of 12 ml for heifers and 19 ml for cows) starting on days 8-12 of the estrus cycle. Inseminations began 12h after the onset of estrus and were performed two to four times at 9-15 h intervals. Low-dose X-sorted inseminates were deposited into uterine horns and unsorted semen was placed into the uterine body. In Experiment 1, on average 70.3 and 75.0% of embryos recovered from heifers, and 48.4 and 100% of embryos recovered from cows were of transferable quality in X-sorted and unsorted groups, respectively. The proportion of transferable female embryos produced approximately doubled when insemination was with X-sorted spermatozoa compared to insemination with unsorted semen (heifers 96.4% versus 41.1%; cows 81.1% versus 39.8%). In Experiment 2, estimated 53.9 and 65.5% of embryos recovered from heifers, and 21.1 and 64.5% of embryos recovered from cows were of transferable quality in X-sorted and unsorted groups, respectively. Proportions of unfertilized oocytes were 21.1 and 10.6% for heifers and 56.0 and 14.4% for cows in X-sorted and unsorted groups, respectively. Consequently, cows inseminated with X-sorted spermatozoa produced significantly smaller proportions of transferable embryos (p<0.005) and significantly larger proportions of unfertilized oocytes (p<0.001) than those inseminated with unsorted semen. Proportions of quality 1 or degenerated embryos were similar for the two treatments in both heifers and cows. Within treatments, bulls did not significantly affect the proportions of transferable, unfertilized or degenerated oocytes/embryos. It was concluded that using low-dose X-sorted spermatozoa rather than normal-dose unsorted semen for the insemination of superovulated embryo donors can improve the proportion of transferable female embryos produced but this potential may not be achieved in commercial practice, particularly in cows, because of reduced fertilization rates when using low doses of X-sorted spermatozoa.

Lung function and bronchial hyper-responsiveness 11 years after hospitalization for bronchiolitis.

AIM: Atopic infants hospitalized for wheezing not caused by respiratory syncytial virus (RSV) carry the highest risk for later asthma. In the present paper, early risk factors for later lung function abnormalities and for bronchial hyper-responsiveness (BHR) were evaluated in 81 children, hospitalized for bronchiolitis in infancy, at the median age of 12.3 years. METHODS: The basic data, including data on atopy in children and viral aetiology of bronchiolitis, had been collected on entry to the study at less than 2 years of age. Lung function was studied by flow-volume spirometry (FVS), and BHR by methacholine and exercise challenge tests 11.4 years after hospitalization during infancy. RESULTS: RSV aetiology of bronchiolitis was associated with reduced forced vital capacity (FVC; 93.65% of predicted +/- 11.05 vs. 99.57%+/- 12.59, p = 0.009). Early sensitization to inhalant allergens (OR 12.59, 95% CI 2.30-68.77) and maternal smoking during pregnancy (OR 4.58, 95% CI 1.28-16.39) were associated with BHR to exercise, and early atopic dermatitis (OR 3.48, 95% CI 1.09-11.10) was associated with BHR to methacholine. CONCLUSIONS: RSV bronchiolitis was associated with a restrictive pattern of lung function. Early atopy and maternal smoking during pregnancy may play a role in the development and persistence of BHR.

Hyperbaric oxygen therapy in acute necrotizing infections with a special reference to the effects on tissue gas tensions.

Clostridial gas gangrene and perineal necrotizing fasciitis or Fournier's gangrene are rare but serious infections with an acute onset, rapid progression, systemic toxemia and a high mortality rate. The aim of this study was to investigate the efficacy of surgery, antibiotic treatment, surgical intensive care and in particular the role of hyperbaric oxygen (HBO) in the management of these infections. An experimental rat model was used to investigate the possibilities for measuring tissue oxygen and carbon dioxide tensions during hyperbaric oxygen treatment. In addition to this preliminary experimental study, Silastic tube tonometer and capillary sampling techniques were tested to measure the effect of hyperbaric oxygen treatment on subcutaneous oxygen and carbon dioxide tensions in patients with necrotizing fasciitis and healthy controls. Between January 1971 and April 1997, 53 patients with Clostridial gas gangrene were treated in the Department of Surgery, University of Turku. The patients underwent surgical debridement, broad spectrum antibiotic therapy and a series of hyperbaric oxygen treatments at 2.5 atmospheres absolute pressure (ATA). Twelve patients died (22.6%). Hyperbaric oxygen therapy in gas gangrene seems to be life-, limb- and tissue saving. Early diagnosis remains essential. Patient survival can be improved if the disease is recognized early and appropriate therapy instituted promptly. Between February 1971 and September 1996, 33 patients with perineal necrotizing fasciitis were treated in the Department of Surgery, University of Turku. The management included surgical debridement of the necrotic tissue with incisions and drainage of the involved areas, antibiotic therapy, hyperbaric oxygen treatment at 2.5 ATA pressure and surgical intensive care. Three patients died giving a mortality rate of 9.1%. The survivors received hyperbaric oxygen therapy for 2-12 times. Our results indicate that hyperbaric oxygenation is an important therapeutic adjunct in the treatment of Fournier's gangrene. Electrical equipment should not be used unsheltered in a hyperbaric chamber due to the increased risk of fire. The subcutaneous tissue gas tensions of rats were therefore measured using a subcutaneously implanted Silastic tube tonometer and a capillary sampling technique. The method was successfully adapted to hyperbaric conditions. The subcutaneous oxygen tension levels increased five fold and the carbon dioxide tension levels two fold compared to initial levels. The PO2 and PCO2 of subcutaneous tissue and arterial blood were measured directly in six patients with necrotizing fasciitis and three healthy volunteers in normobaric conditions and during hyperbaric oxygen exposure at 2.5 ATA pressure. The measurements were carried out in healthy tissue and at the same time in the vicinity of the infected area of the patients. During HBO at 2.5 ATA subcutaneous oxygen tensions increased several fold from baseline values and carbon dioxide tensions also increased, but to a lesser degree in both healthy and infected tissues. When examining the subcutaneous PO2 levels measured from patients with necrotizing fasciitis, the PO2 was regularly higher in the vicinity of the infected area than in healthy tissue. In general, HBO treatment resulted in a marked increase in tissue oxygenation in both healthy tissue and in the vicinity of infected tissue. The hyper-oxygenated tissue zone surrounding the infected area may be of significance in preventing the extension of invading microorganisms.