Are biomechanics during gait associated with the structural disease onset and progression of lower limb osteoarthritis? A systematic review and meta-analysis

OBJECTIVE

To evaluate if gait biomechanics are associated with increased risk of structurally diagnosed disease onset or progression of lower limb osteoarthritis (OA).

METHOD

A systematic review of Medline and Embase was conducted from inception to July 2021. Two reviewers independently screened records, extracted data and assessed risk of bias. Included studies reported gait biomechanics at baseline, and either structural imaging or joint replacement occurrence in the lower limb at follow-up. The primary outcome was the Odds Ratio (OR) (95% confidence interval (CI)) of the association between biomechanics and structural OA outcomes with data pooled for meta-analysis.

RESULTS

Twenty-three studies reporting 25 different biomechanical metrics and 11 OA imaging outcomes were included (quality scores ranged 12-20/21). Twenty studies investigated knee OA progression; three studies investigated knee OA onset. Two studies investigated hip OA progression. 91% of studies reported a significant association between at least one biomechanical variable and OA onset or progression. There was an association between frontal plane biomechanics with medial tibiofemoral and hip OA progression and sagittal plane biomechanics with patellofemoral OA progression. Meta-analyses demonstrated increased odds of medial tibiofemoral OA progression with greater baseline peak knee adduction moment (KAM) (OR: 1.88 [95%CI: 1.08, 3.29]) and varus thrust presence (OR: 1.97 [95%CI: 1.32, 2.96]).

CONCLUSION

Evidence suggests that certain gait biomechanics are associated with an increased odds of OA onset and progression in the knee, and progression in the hip.

REGISTRATION NUMBER

PROSPERO CRD42019133920.

Improved Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season

We present results from an analysis of all data taken by the BICEP2, Keck Array, and BICEP3 CMB polarization experiments up to and including the 2018 observing season. We add additional Keck Array observations at 220 GHz and BICEP3 observations at 95 GHz to the previous 95/150/220  GHz dataset. The Q/U maps now reach depths of 2.8, 2.8, and 8.8  μK_{CMB} arcmin at 95, 150, and 220 GHz, respectively, over an effective area of ≈600 square degrees at 95 GHz and ≈400 square degrees at 150 and 220 GHz. The 220 GHz maps now achieve a signal-to-noise ratio on polarized dust emission exceeding that of Planck at 353 GHz. We take auto- and cross-spectra between these maps and publicly available WMAP and Planck maps at frequencies from 23 to 353 GHz and evaluate the joint likelihood of the spectra versus a multicomponent model of lensed ΛCDM+r+dust+synchrotron+noise. The foreground model has seven parameters, and no longer requires a prior on the frequency spectral index of the dust emission taken from measurements on other regions of the sky. This model is an adequate description of the data at the current noise levels. The likelihood analysis yields the constraint r_{0.05}<0.036 at 95% confidence. Running maximum likelihood search on simulations we obtain unbiased results and find that σ(r)=0.009. These are the strongest constraints to date on primordial gravitational waves.

Constraints on Primordial Gravitational Waves Using Planck, WMAP, and New BICEP2/Keck Observations through the 2015 Season

We present results from an analysis of all data taken by the bicep2/Keck CMB polarization experiments up to and including the 2015 observing season. This includes the first Keck Array observations at 220 GHz and additional observations at 95 and 150 GHz. The Q and U maps reach depths of 5.2, 2.9, and 26  μK_{CMB} arcmin at 95, 150, and 220 GHz, respectively, over an effective area of ≈400 square degrees. The 220 GHz maps achieve a signal to noise on polarized dust emission approximately equal to that of Planck at 353 GHz. We take auto and cross spectra between these maps and publicly available WMAP and Planck maps at frequencies from 23 to 353 GHz. We evaluate the joint likelihood of the spectra versus a multicomponent model of lensed-ΛCDM+r+dust+synchrotron+noise. The foreground model has seven parameters, and we impose priors on some of these using external information from Planck and WMAP derived from larger regions of sky. The model is shown to be an adequate description of the data at the current noise levels. The likelihood analysis yields the constraint r_{0.05}<0.07 at 95% confidence, which tightens to r_{0.05}<0.06 in conjunction with Planck temperature measurements and other data. The lensing signal is detected at 8.8σ significance. Running a maximum likelihood search on simulations we obtain unbiased results and find that σ(r)=0.020. These are the strongest constraints to date on primordial gravitational waves.

Validation of a short cognitive battery to screen for fitness-to-drive of people with multiple sclerosis

BACKGROUND AND PURPOSE

Some symptoms of multiple sclerosis (MS) affect driving. In a recent study, performance on five cognitive tests predicted the on-road test performance of individuals with relapsing-remitting MS with 91% accuracy, 70% sensitivity and 97% specificity. However, the accuracy with which the battery will predict the driving performance of a different cohort that includes all types of MS is unknown.

METHODS

Participants (n = 118; 48 ± 9 years of age; 97 females) performed a comprehensive off-road evaluation that lasted about 3 h and a standardized on-road test that lasted approximately 45 min over a 2-day period within the same week. Performance on the five cognitive tests was used to predict participants' performance on the standardized on-road test.

RESULTS

Performance on the five tests together predicted outcome of the on-road test with 82% accuracy, 42% sensitivity and 90% specificity.

CONCLUSIONS

The accuracy of predicting the on-road performance of a new MS cohort using performance on the battery of five cognitive tests remained very high (82%). The battery, which was administrable in <45 min and cost ~$150, was better at identifying those who actually passed the on-road test (90% specificity). The sensitivity (42%) of the battery indicated that it should not be used as the sole determinant of poor driving-related cognitive skills. A fail performance on the battery should only imply that more comprehensive testing is warranted.

Spatial and Temporal Variation in the Effects of Climatic Variables on Dugong Calf Production

Knowledge of the relationships between environmental forcing and demographic parameters is important for predicting responses from climatic changes and to manage populations effectively. We explore the relationships between the proportion of sea cows (Dugong dugon) classified as calves and four climatic drivers (rainfall anomaly, Southern Oscillation El Niño Index [SOI], NINO 3.4 sea surface temperature index, and number of tropical cyclones) at a range of spatially distinct locations in Queensland, Australia, a region with relatively high dugong density. Dugong and calf data were obtained from standardized aerial surveys conducted along the study region. A range of lagged versions of each of the focal climatic drivers (1 to 4 years) were included in a global model containing the proportion of calves in each population crossed with each of the lagged versions of the climatic drivers to explore relationships. The relative influence of each predictor was estimated via Gibbs variable selection. The relationships between the proportion of dependent calves and the climatic drivers varied spatially and temporally, with climatic drivers influencing calf counts at sub-regional scales. Thus we recommend that the assessment of and management response to indirect climatic threats on dugongs should also occur at sub-regional scales.

Improved Constraints on Cosmology and Foregrounds from BICEP2 and Keck Array Cosmic Microwave Background Data with Inclusion of 95 GHz Band

We present results from an analysis of all data taken by the BICEP2 and Keck Array cosmic microwave background (CMB) polarization experiments up to and including the 2014 observing season. This includes the first Keck Array observations at 95 GHz. The maps reach a depth of 50 nK deg in Stokes Q and U in the 150 GHz band and 127 nK deg in the 95 GHz band. We take auto- and cross-spectra between these maps and publicly available maps from WMAP and Planck at frequencies from 23 to 353 GHz. An excess over lensed ΛCDM is detected at modest significance in the 95×150 BB spectrum, and is consistent with the dust contribution expected from our previous work. No significant evidence for synchrotron emission is found in spectra such as 23×95, or for correlation between the dust and synchrotron sky patterns in spectra such as 23×353. We take the likelihood of all the spectra for a multicomponent model including lensed ΛCDM, dust, synchrotron, and a possible contribution from inflationary gravitational waves (as parametrized by the tensor-to-scalar ratio r) using priors on the frequency spectral behaviors of dust and synchrotron emission from previous analyses of WMAP and Planck data in other regions of the sky. This analysis yields an upper limit r_{0.05}<0.09 at 95% confidence, which is robust to variations explored in analysis and priors. Combining these B-mode results with the (more model-dependent) constraints from Planck analysis of CMB temperature plus baryon acoustic oscillations and other data yields a combined limit r_{0.05}<0.07 at 95% confidence. These are the strongest constraints to date on inflationary gravitational waves.

A species comparison of the effects of changing perfusion pressure on blood flow and metabolic heat production in the myocardium

1. A heated thermocouple technique (internal calorimetry) has been used to investigate blood flow and heat production responses in the myocardium to changing blood pressure in monkeys, dogs, rabbits, guinea-pigs and rats. 2. Perfusion experiments (isolated guinea-pig and dog hearts) showed linear relations between conductivity increment and coronary blood flow up to 1 x 5 ml. g(-1) min(-1) (dog heart perfused with blood) and 5 ml. g(-1) min(-1) (guinea-pig heart perfused with saline). This relation was the same in the beating and non-beating heart. 3. In rabbits, guinea-pigs and rats the relation between flow (conductivity increment) and blood pressure was linear. In contrast, in monkeys and dogs, over the range 100-40 mm Hg, little change in blood flow occurred. After the injection of procaine around the stellate ganglion, the relation between pressure and flow in both species was linear. It is suggested that the constancy of blood flow displayed in the monkey and dog over this blood pressure range was due to the activity of adrenergic rasodilator fibres. 4. Evidence is adduced to show an increased myocardial heat production when systemic arterial pressure fell below about 60 mm Hg. This was not affected by cardiac denervation. The possible significance of this effect is discussed.

Attitudes of suburban Western Australians to proposed cat control legislation

OBJECTIVE

To determine the knowledge, attitudes and practices of cat-owners and non-owners in suburban Perth, Western Australia, on issues relating to proposed local government regulation of cat-ownership.

DESIGN

The 1,261 respondents to a mailed survey were ranked on issues regarding restrictions on cat-ownership and cat roaming (control scale), attitudes to wildlife in suburbia and putative impacts of cats on wildlife (wildlife scale), knowledge of cat behaviour and husbandry (knowledge scale) and attitudes and practices regarding cat sterilisation (sterilisation scale). Age, gender and cat-ownership status of the survey respondents were explored to see if any of these factors influenced the position of respondents on the scales.

RESULTS

Cat-owners, particularly female owners, scored significantly higher on the knowledge scale than non-owners, whilst non-owners scored significantly higher than cat-owners on the control and wildlife scales. Women were more likely to favour compulsory sterilisation of pet cats than men, but men were more willing to implement controls on cat-ownership. Age was also a significant factor, with older people more willing to implement controls. Analysis of specific questions showed that both cat-owners and non-owners agreed that there was a need for cat control legislation and supported measures such as compulsory sterilisation, registering of cats, restricting cats' ability to roam and stipulating a maximum number of cats per property. Nevertheless, both groups rejected the idea that local governments should enforce cat-free zones.

CONCLUSION

Cat legislation that avoids or educates about the contentious issue of cat-free zones should receive solid community support.

Respiration and heart rate at the surface between dives in northern elephant seals

All underwater activities of diving mammals are constrained by the need for surface gas exchange. Our aim was to measure respiratory rate (fb) and heart rate (fh) at the surface between dives in free-ranging northern elephant seals Mirounga angustirostris. We recorded fb and fh acoustically in six translocated juveniles, 1.8-2. 4 years old, and three migrating adult males from the rookery at Ano Nuevo, California, USA. To each seal, we attached a diving instrument to record the diving pattern, a satellite tag to track movements and location, a digital audio tape recorder or acoustic datalogger with an external hydrophone to record the sounds of respiration and fh at the surface, and a VHF transmitter to facilitate recovery. During surface intervals averaging 2.2+/−0.4 min, adult males breathed a mean of 32.7+/−5.4 times at a rate of 15. 3+/−1.8 breaths min(−)(1) (means +/− s.d., N=57). Mean fh at the surface was 84+/−3 beats min(−)(1). The fb of juveniles was 26 % faster than that of adult males, averaging 19.2+/−2.2 breaths min(−)(1) for a mean total of 41.2+/−5.0 breaths during surface intervals lasting 2.6+/−0.31 min. Mean fh at the surface was 106+/−3 beats min(−)(1). fb and fh did not change significantly over the course of surface intervals. Surface fb and fh were not clearly associated with levels of exertion, such as rapid horizontal transit or apparent foraging, or with measures of immediately previous or subsequent diving performance, such as diving duration, diving depth or swimming speed. Together, surface respiration rate and the duration of the preceding dive were significant predictors of surface interval duration. This implies that elephant seals minimize surface time spent loading oxygen depending on rates of oxygen uptake and previous depletion of stores.

Collaborative interactions between MEF-2 and Sp1 in muscle-specific gene regulation

Previous investigations have demonstrated synergistic interactions in vivo between CCAC and A/T-rich nucleotide sequence motifs as functional components of muscle-specific transcriptional enhancers. Using CCAC and A/T-rich elements from the myoglobin and muscle creatine kinase (MCK) gene enhancers, Sp1 and myocyte-specific enhancer factor-2 (MEF-2) were identified as cognate binding proteins that recognize these sites. Physical interactions between Sp1 and MEF-2 were demonstrated by immunological detection of both proteins in DNA binding complexes formed in vitro by nuclear extracts in the presence of only the A/T sequence motif, by coprecipitation of recombinant MEF-2 in the presence of a glutathione-S-transferase-Sp1 fusion protein bound to glutathione beads, and by a two-hybrid assay in Saccharomyces cerevisiae. The interaction with Sp1 in vitro and in vivo is specific for MEF-2 and was not observed with serum response factor, a related MADS domain protein. Forced expression of Sp1 and MEF-2 in insect cells otherwise lacking these factors promotes synergistic transcriptional activation of a promoter containing binding sites for both proteins. These data expand the repertoire of functional and physical interactions between lineage-restricted (MEF-2) and ubiquitous (Sp1) transcription factors that may be important for myogenic differentiation.

Peroxynitrite inhibits leukocyte-endothelial cell interactions and protects against ischemia-reperfusion injury in rats

Peroxynitrite (ONOO-) anion, formed by the interaction of superoxide with nitric oxide (NO), has previously been implicated as a cytotoxic agent. However, the effects of this free radical species on neutrophil (PMN)-endothelial cell interactions is largely unknown. We investigated the direct actions of ONOO- on PMN adhesion to endothelial cells in vitro and in vivo, as well as the effects of ONOO- on PMN-mediated myocardial ischemia-reperfusion injury. In vitro, peroxynitrite (100-1,000 nM) inhibited the adhesion of rat PMNs to the endothelium of isolated thrombin- or H2O2-stimulated rat mesenteric artery (P < 0.01 vs. thrombin or H2O2 alone). In vivo, in the rat mesentery, thrombin (0.5 U/ml) or N(G)-nitro-L-arginine-methyl ester (50 microM) significantly increased venular leukocyte rolling and adherence, which were also significantly (P < 0.01) attenuated by ONOO (800 nM) accompanied by reduced P-selectin expression on the endothelial cell surface. Isolated perfused rat hearts were subjected to global ischemia and reperfusion with rat PMNs (10(8) cells), which resulted in profound cardiac depression (i.e., a marked reduction in left ventricular developed pressure and maximal rate of development of left ventricular pressure). Infusion of ONOO- reversed the myocardial contractile dysfunction of ischemic-reperfused rat hearts to near baseline levels, and markedly attenuated the accumulation of PMNs in the postischemic heart. The present study provides strong evidence that nanomolar concentrations of ONOO- both inhibit leukocyte-endothelial cell interactions and exert cytoprotective effects in myocardial ischemia-reperfusion injury. Furthermore, our results suggest that the inhibition of P-selectin expression by peroxynitrite is a key mechanism of the modulatory actions of ONOO- on leukocyte-endothelial cell interactions.

Postnatal development and plasticity of specialized muscle fiber characteristics in the hindlimb

Recent progress in defining molecular components of pathways controlling early stages of myogenesis has been substantial, but regulatory factors that govern the striking functional specialization of adult skeletal muscle fibers in vertebrate organisms have not yet been identified. A more detailed understanding of the temporal and spatial patterns by which specialized fiber characteristics arise may provide clues to the identity of the relevant regulatory factors. In this study, we used immunohistochemical, in situ hybridization, and Northern blot analyses to examine the time course and spatial characteristics of expression of myoglobin protein and mRNA during development of the distal hindlimb in the mouse. In adult animals, myoglobin is expressed selectively in oxidative, mitochondria-rich, fatigue-resistant myofibers, and it provides a convenient marker for this particular subset of specialized fibers. We observed only minimal expression of myoglobin in the hindlimb prior to the second day after birth, but a rapid and large (50-fold) induction of this gene in the ensuing neonatal period. Myoglobin expression was limited, however, to fibers located centrally within the limb which coexpress myosin isoforms characteristic of type I, IIA, and IIX fibers. This induction of myoglobin expression within the early postnatal period was accompanied by increased expression of nuclear genes encoding mitochondrial proteins, and exhibited a time course similar to the upregulation of myoglobin and mitochondrial proteins, and exhibited a time course similar to the upregulation of myoglobin and mitochondrial protein expression that can be induced in adult muscle fibers by continuous motor nerve stimulation. This comparison suggests that progressive locomotor activity of neonatal animals may provide signals which trigger the development of the specialized features of oxidative, fatigue-resistant skeletal muscle fibers.

Synergistic interactions between heterologous upstream activation elements and specific TATA sequences in a muscle-specific promoter

Previous investigations have defined three upstream activation elements--CCAC, A/T, and TATA sequences--necessary for muscle-specific transcription of the myoglobin gene. In the present study, we demonstrate that these three sequences elements, prepared as synthetic oligonucleotide cassettes, function synergistically to constitute a cell-type-specific transcription unit. Previously, cognate binding factors that recognize the CCAC and TATA elements were identified. In this study we determine that the A/T element binds two nuclear factors, including myocyte enhancer factor-2 (MEF-2) and an apparently unknown factor we provisionally termed ATF35 (A/T-binding factor, 35 kDa). Mutations that alter in vitro binding of either MEF-2 or ATF35 to this site diminish promoter function in vivo. Functional synergism between factors binding the CCAC and A/T elements is sensitive to subtle mutations in the TATA sequence, recapitulating the unusual preference for specific TATA variants exhibited by the native myoglobin promoter. These results provide new insights into mechanisms that underlie the distinctive pattern of myoglobin gene regulation in mammalian muscle development and lay a foundation for further studies to elucidate general principles of transcriptional control of complex mammalian promoters through combinatorial actions of heterologous transcriptional factors.

The significance of blood levels of IgM, IgA, IgG and IgG subclasses in Sudanese visceral leishmaniasis patients

We developed an ELISA test using leishmania antigenic extracts to detect antigen-specific antibody responses, including subclass and isotype analysis, in visceral leishmaniasis (VL) patients from the Sudan. A total of 92 parasitologically proven patients were compared with cutaneous leishmaniasis, schistosomiasis, malaria, onchocerciasis and tuberculosis patients, as well as with healthy endemic and non-endemic controls. Some VL patients were examined before and after chemotherapy. VL patients showed significantly higher IgG responses compared with all other groups (93.4% sensitivity, 93.7% specificity), and higher (but not significantly) IgM responses. All groups showed low IgA levels. All IgG subclasses, IgG1, 2, 3, and 4, showed higher levels in patients than all other groups, with IgG1 and IgG3 levels being significantly reduced following treatment. The rank order for specificity and sensitivity for IgG subclasses was IgG3 > IgG1 > IgG2 > IgG4.

Sequence elements required for transcriptional activity of the human myoglobin promoter in intact myocardium

To define sequence elements required for myoglobin gene transcription in the intact heart, we examined the expression of a reporter gene under the control of a 380-bp upstream segment (-373 to +7) from the human myoglobin gene in transgenic mouse embryos and after gene transfer into left ventricular myocardium of adult rats. This proximal upstream region was sufficient to direct expression of luciferase selectively in cardiac and skeletal muscle of mouse embryos and to recapitulate the pattern of expression of the endogenous mouse myoglobin gene. This same upstream region was transcriptionally active after injection of plasmid DNA into the left ventricular wall of adult rats. Point mutations within two evolutionarily conserved sequence elements--a cytosine-rich (CCAC-box) motif and an A+T-rich (A/T) motif--severely impaired transcription within the intact heart. Nuclear extracts from neonatal cardiomyocytes contain protein factors that bind to each of these elements in a sequence-specific manner. We conclude that combinatorial interactions between the cognate DNA binding factors that recognize these motifs are necessary for transcriptional activity of the myoglobin upstream region in cardiac muscle.

Rhabdomyosarcoma. A new classification scheme related to prognosis

We classified 159 cases of rhabdomyosarcoma (RMS) according to the conventional scheme adopted by the World Health Organization and a modified conventional scheme established at the National Cancer Institute (NCI), Bethesda, Md. The major modification in the NCI scheme was the inclusion of compact round-cell RMS with scant myogenesis in the group of alveolar RMS despite lack of an alveolar architecture. These tumors were previously considered to be embryonal RMS, but their cytologic features are quite different from those seen in embryonal RMS and are indistinguishable from those encountered in alveolar RMS. These tumors are referred to as "solid alveolar RMS." Survival curves were constructed with the method of Kaplan-Meier and compared with the unstratified and stratified methods of Mantel-Haenszel (with stratification factors being stage, site, and age) and with the Cox regression analysis. Both histologic schemes showed a statistically significant prognostic value in unstratified analyses, but the NCI scheme demonstrated prognostic value even in stratified analyses and in the Cox regression analysis in our series of cases. The data indicate that the NCI scheme can serve as a highly predictive, independent prognostic factor in RMS and that the alveolar category should be expanded to include the solid round-cell RMS, even in the absence of a classic alveolar architecture.

Primary malignant extragonadal germ cell tumors. An analysis of the effect of the effect of radiotherapy

A retrospective analysis was performed on all patients diagnosed with biopsy-proven extragonadal germ cell tumors at the University of Virginia (Charlottesville, VA), The Medical University of South Carolina (Charleston, SC), the Bethesda Naval Hospital (Bethesda, MD), and The Medical College of Virginia (Richmond, VA) for the time period of January 1965 to December 1984. A total of 54 patients were treated with the initial sites of presentation observed: mediastinum, 26; central nervous system, 14; retroperitoneum, eight; and sacrococcygeal region, six. Megavoltage irradiation was used in 44 patients with a dose range of 2400 to 5580 cGy (mean, 4213 cGy). With a minimum follow-up of 4.0 years and a mean follow-up of 10.8 years, the 5-year actuarial survival for the entire population was 57.8%. Local control was achieved in 26 of 44 (59%) of the irradiated population. Factors of prognostic significance included histologic type at presentation, site of presentation, and radiation doses greater than or equal to 4000 cGy. Radiotherapy appears to be an effective modality in patients with extragonadal seminomas; however, the nonseminomatous tumors do not appear to be as radioresponsive.

Ten-year survival of patients with small-cell lung cancer treated with combination chemotherapy with or without irradiation

We evaluated the 10- to 15-year outcome of 252 patients with small-cell lung cancer entered into therapeutic clinical trials with or without chest and cranial irradiation. Thirty-two patients (13%) survived free of cancer for 2 or more years. Twelve patients (5%) survived at least 10 years free of cancer, and 10 patients are currently alive and free of cancer beyond 10 years. Six of these 10 patients currently function at a level comparable with that before diagnosis. The other 22 patients who were cancer-free at 2 years have died. Nine patients died from recurrent small-cell lung cancer 2 to 6.2 years after initiation of chemotherapy. Five died from non-small-cell lung cancer, three died of other malignancies, and five died of causes other than cancer. A small fraction of patients with small-cell lung cancer are cured of their original malignancy, but these patients remain at high risk for second cancers and death from other causes.

Neurologic, computed cranial tomographic, and magnetic resonance imaging abnormalities in patients with small-cell lung cancer: further follow-up of 6- to 13-year survivors

To determine the subsequent evolution of neurologic, neuropsychologic, and intracranial anatomic findings in long-term survivors of small-cell cancer, we repeated an evaluation done 4 years previously in patients 6 to 13 years after treatment. Fifteen patients were reevaluated with a history and physical examination, mental status examination, neuropsychologic testing, computed cranial tomographic (CCT) scans, and magnetic resonance imaging (MRI). All but one was ambulatory and none were institutionalized. Thirteen of 15 had neurologic complaints, 10 of 15 had an abnormal neurologic examination, seven of 14 had an abnormal mental status examination, 12 of 14 had abnormal neuropsychologic testing, 12 of 15 had abnormal CCT scans, and seven of 15 had white-matter abnormalities on MRI scans. No dramatic decline in performance status, functional status, neurologic symptoms, or neurologic examination occurred in these patients with 4 years of additional follow-up. More patients showed a decline in mental status examinations and neuropsychologic testing than demonstrated improvement. Anatomic studies showed no dramatic changes in the CCT scans and MRI confirmed these findings. From these data we conclude that there is a slow decline in neuropsychologic function in some of the patients surviving more than 6 years from a diagnosis of small-cell lung cancer. The anatomic abnormalities documented by CCT scans and MRI are more frequent in patients with abnormal neuropsychologic function.

Primary malignant mediastinal germ-cell tumors and the contribution of radiotherapy: a southeastern multi-institutional study

A retrospective review was performed by a multi-institutional study group to determine the contribution of radiotherapy to the management of primary malignant mediastinal germ-cell tumors. Twenty-seven patients diagnosed with a primary mediastinal germ-cell tumor between January 1965 and July 1985 form the basis of this study. Twenty-five of the 27 patients were male. Thirteen patients' tumors were diagnosed as seminoma and the remaining 14 patients' tumors had other germ-cell histologies. The single most important prognostic factor was histology, with a 5-year actuarial survival of 100% for the seminomas and only 8.8% for the remaining germ-cell varieties. If total surgical extirpation is not possible, biopsy may be adequate. Of the patients with seminoma, 11 of 12 had local control, and 3 of the 12 patients were treated with doses between 3,000 and 3,100 cGy. High doses for this variety of mediastinal germ-cell tumor might not be required. For the germ-cell tumors other than seminoma, no patient had local control with doses over the range of 3,000-4,750 cGy.

Right hemicolectomy and ileal resection with primary reanastomosis for irradiation injury of the terminal ileum

Injury to the small intestine from pelvic irradiation increases in frequency when extended treatment fields are utilized and when radiation therapy follows a major abdominal operation. Recommended surgical correction of such injury has been intestinal bypass to avoid the excessive morbidity and mortality from anastamotic leaks associated with primary resection and anastomosis. Since 1980, eight patients with extensive ileal injury secondary to irradiation have been seen at the Naval Hospital Bethesda, Maryland. All patients had previously undergone an abdominal operation and three patients had irradiation utilizing extended fields. In all cases, right hemicolectomy and extended ileal resection were performed with primary anastamosis of the ileum to the ascending colon or the transverse colon. Operating time averaged 4 1/2 hr utilizing hand closure anastomoses and 2 1/2 hr with stapled anastomoses. All patients received postoperative hyperalimentation and six of eight patients received preoperative hyperalimentation. One operative death occurred in a patient with intestinal perforation who required multiple resections. The remaining seven patients experienced no serious complications and had rapid return of bowel function. Our experience indicates that wide ileal resection with right hemicolectomy and primary reanastomosis is an acceptable alternative to intestinal bypass for the treatment of severe irradiation injury, especially when performed with gastrointestinal stapling devices.

Transmural distribution of intramyocardial pressure measured by micropipette technique

A technique is presented for measuring intramyocardial pressure (IMP) in beating hearts using the servo-nulling pressure transducer equipped with polyethylene micropipettes (ID less than 12 micron). The static and dynamic response characteristics of the system were tested in a pressurized, saline-filled container as well as in a pressurized, hollow, gelatin cylinder. The system was then used to measure IMP in vivo in the hearts of 12 dogs during stable cardiac performance and with aortic constriction. In vitro response characteristics were found to be satisfactory for accurate reproduction of cardiovascular waveforms. Peak systolic IMP was not found to exceed the simultaneously recorded left intraventricular pressure (LVP). Furthermore, the slope of the regression line relating the IMP to LVP during systole is linearly related (slope 0.98) to the depth of the micropipette tip in the ventricular wall, as normalized to total wall thickness. Diastolic IMP ranged between 1 +/- 1 (minimum during the cardiac cycle) and 4 +/- 2 mmHg (end diastolic) at associated LVP of 2 +/- 2 and 5 +/- 2 mmHg (mean +/- SD), respectively.

Effect of nicotine on blood flow, oxygen consumption and glucose uptake in the canine small intestine

Resting blood flow, arterio-venous glucose and oxygen (A-V)O2 differences, glucose uptake and oxygen consumption by a segment of the upper jejunum were measured in anaesthetized dogs. Systemic arterial pressure was also measured. The effect of nicotine infusion (25 micrograms kg-1 i.v., over 10 min) on these measurements was recorded in untreated dogs, in dogs treated with propranolol (0.5 mg kg-1) to produce beta-adrenoceptor blockade and in dogs after alpha 1-adrenoceptor blockade with prazosin (0.2 mg kg-1). Nicotine cause a significant pressor response during infusion and a hypotensive response during the post infusion period. Propranolol did not significantly affect these results. Jejunal blood flow increased in the first half of nicotine infusion in both the untreated and beta-blocked animals. Vascular resistance was reduced during nicotine infusion and the decrease persisted post infusion in the beta-blocked group. In the untreated group (A-V)O2 was significantly reduced during the first 5 min of nicotine infusion, thereafter it returned to control levels, then rose significantly above control level, post infusion. beta-Adrenoceptor blockade had little effect on these responses to nicotine. When oxygen consumption was calculated it was found that nicotine had little effect during or after infusion. Nicotine caused significant hyperglycaemia during and for about 1 h after infusion. Tissue release of glucose was occasionally observed following the infusion. beta-Adrenoceptor blockade reduced the hyperglycaemia caused by nicotine. beta-Blockade alone increased uptake and nicotine caused a further three to four fold increase. Prazosin abolished the effects that were observed in the untreated and the alpha-blocked animals. 6 The present findings, related to our previous observations on the effects of catecholamines on glucose uptake by the bowel, are consistent with the hypothesis that nicotine has its action on bowel glucose uptake or release through its well-established action in releasing catecholamines and in activating beta-adrenoceptors. The responses are not related to oxygen utilization.

Functional and morphological changes in the microcirculation of the dog following acute coronary artery ligation

Acute ligation of the anterior descending coronary artery in the dog had little immediate effect on heat clearance but immediately lowered heat production, which fell to its minimum level in 1/2 hr, after which it began to recover; recovery was complete in 6 hr. After 1/2 hr heat clearance also began to fall and reached a minimum level in 1 1/2 hr. Ligation increased oxygen extraction but reduced oxygen consumption markedly though temporarily. Complete recovery followed. After 3 months, there was full recovery in flow, oxygen extraction ratio, and oxygen consumption mVO2. In morphological studies using Microfil injections soon after ligation, capillaries failed to fill retrogradely, though network vessels were perfused. After 1 hr of acute artery ligation, capillaries still did not perfuse but by 3 hr there was some reperfusion. After 6 hr there was marked capillary reperfusion. In dogs kept for 3 months after ligation the microcirculation was normal. These studies confirm that immediate circulatory failure occurred in capillaries (probably critical closure) which accounts for the immediate fall in venous outflow, heat production, and mVO2. Flow continued in network vessels which traversed the ischemic zone without perfusing capillaries. These results are contrasted with the findings of some other workers who found a continued functional decline leading to infarction. The present results were accounted for by closure and reopening to capillaries.

T cell-replacing factor for glucocorticosteroid-induced immunoglobulin production. A unique steroid-dependent cytokine

Glucocorticosteroids (GCS) added to otherwise unstimulated cultures of human peripheral blood mononuclear cells (PBMC) induce the synthesis and secretion of all classes of immunoglobulin. The magnitude of this response is similar to that seen with other polyclonal B cell activators such as pokeweed mitogen (PWM), and like that of PWM, the steroid effect is dependent on both T cells and monocytes. To determine the cellular target for GCS in these cultures, separated populations of T cells and non-T cells were preincubated with steroids and then recombined. No immunoglobulin was produced in any of these preincubation experiments. As a different approach to this question, supernatants were collected from various cell populations following stimulation with PWM, concanavalin A (Con A), phytohemagglutinin (PHA), alloantigens, or GCS. These supernatants were tested for their effects on GCS-induced Ig production by B cells. Supernatants from 3-d cultures of unstimulated, as well as GCS-treated, PBMC contained a T cell-replacing factor that permitted T-depleted PBMC to produce Ig upon steroid stimulation. This supernatant factor (TRF-S) could be produced in the absence of steroid stimulation, but both the factor and GCS were necessary for the induction of Ig synthesis. Production of the TRF-S required the presence of both T cells and adherent cells in culture and was found in the highest concentrations at 3-4 d of culture. Supernatants from cultures stimulated with PWM, PHA, Con A, and alloantigens did not contain detectable TRF-S activity, and TRF-S was unable to replace helper T cells for PWM-induced Ig production. TRF-S required the presence of adherent cells in the T cell-depleted responder population for its action. Further, it was effective in inducing Ig production along with GCS in the presence of a sufficient concentration of cyclosporin A to block all T cell helper activity for primary responses of PBMC to PWM or GCS. TRF-S was inactivated by trypsin treatment, heating to 56 degrees C, freezing, lyophilization, and storage at 4 degrees C for greater than 3 wk. Its molecular weight is probably 10,000 daltons or more, since TRF-S activity is not rapidly dialyzable. These experiments indicate that GCS-induced Ig production by human B cells does not require the presence of intact T cells in the cultures and therefore the steroids are not exerting their influence directly on T suppressor or T helper cells. Furthermore, they demonstrate a previously unrecognized cytokine that induces the differentiation of human B cells to Ig production in the presence of GCS.

The effect of catecholamines on intestinal glucose and oxygen uptake in the dog

Using the anaesthetized dog, continuous recording was made of the oxygen and glucose contents of the artery and the vein draining the upper jejunum. Flow was also measured and results expressed as differences in oxygen and glucose between the aorta and the jejunal vein (a-v), also as oxygen consumption and glucose uptake. Resting glucose uptake was greater than could be accounted for on the basis of oxidation. When adrenaline (1 microgram/kg. min) or noradrenaline (2 micrograms/kg. min) was infused intravenously, oxygen uptake rose by about 50% whereas glucose uptake rose by 300-500%; moreover, the rise in glucose uptake was apparent before the rise in oxygen uptake. The beta-blocking agent, propranolol (0 X 5 mg/kg. min) had no effect on oxygen uptake but caused a three-fold rise in glucose uptake. Subsequently infusion of adrenaline had no effect on oxygen uptake and no effect on glucose uptake. However, on stopping the infusion there was a marked drop in glucose uptake, which was not maintained. It is suggested that the effects of catecholamines may be due to altered arterial blood glucose levels and that the jejunum may play a role in glucose homeostasis which requires the action of beta receptors.

Effect of cold exposure on various sites of core temperature measurements

Rectal, esophageal, auditory canal, gastrointestinal tract, and sublingual temperature were recorded on five young Caucasian males who, in an environment of -32 degrees C and 11-km/h wind, sat during one 90-min exposure and walked on a treadmill at 2.9 km/h during another. The clothing permitted cooling of their torsos while giving adequate protection to their extremities. Control exposures involved subjects sitting in still air at 24-26 degrees C dressed only in thermal underwear. In the control environment all of the internal body temperatures measured gave comparable and consistent values; however, cold exposure affected the various sites differently. Esophageal temperatures fluctuated rapidly as a result of subjects swallowing cold saliva. Sublingual temperatures were below the lower limit of a clinical thermometer, possibly because of facial cooling. Auditory canal temperatures were low, perhaps also because of facial cooling. Rectal temperatures were high as were the gastrointestinal tract temperatures, due perhaps to local heat production in response to cold stimulation. Metabolic rate increased initially in the cold and again toward the end of the cold exposure.

Immunoglobulin production induced in vitro by glucocorticoid hormones: T cell-dependent stimulation of immunoglobulin production without B cell proliferation in cultures of human peripheral blood lymphocytes

The direct effects of steroid hormones on the production of immunoglobulins and DNA synthesis by human T and B lymphocytes was evaluated in cultures of peripheral blood mononuclear cells. As detected by a reverse hemolytic plaque assay, the addition of 0.1 mM to 10 nM hydrocortisone to lymphocytes in culture in the absence of other stimulants or mitogens, resulted in the dramatic induction of immunoglobulin production with responses comparable to those seen in similar cultures stimulated with pokeweed mitogen. Steroid-stimulated immunoglobulin production was first seen after 48 h and peaked at 8-10 d of culture. The production of IgG, IgA, and IgM was induced following incubation with steroid. Glucocorticoids, but not estrogens or androgens, were capable of mediating this effect, and only compounds with affinity for the glucocorticoid receptor were active. The induction of immunoglobulin production was dependent on both T cells and monocytes; cultures depleted of either cell type did not produce immunoglobulin when stimulated with glucocorticoid hormones. Proliferation of B cells or T cells could not be detected by [3H]thymidine incorporation or total cell recovery from steroid-stimulated cultures, even though such cultures demonstrated marked increases in immunoglobulin production. The mechanism responsible for this functional maturation of B cells to become high rate immunoglobulin producing cells is as yet undefined, although it appears to involve more than merely steroid mediated inactivation of suppressor T cells.

Ontogeny of humoral immune function in normal chickens: a comparison of immunoglobulin-secreting cells in bone marrow, spleen, lungs and intestine

A reverse haemolytic plaque was employed to study the ontogeny of immunoglobulin (Ig) secreting cells of either IgG, IgA, or IgM class in normal chickens. After hatching, IgM-secreting cells were detectable in the spleen by 3 days of age whereas IgG- and IgA-secreting cells were first noted at 6 days. Adult levels of Ig-secreting cells of all three classes were attained by 31 days of age in bone marrow and two separate lymphoid populations (lamina propria and intraepithelial lymphocytes). By contrast, adult levels of Ig-secreting cells were not obtained in either the spleen or the lungs until after 50 days of age. In the case of the spleen, the delay in attainment of adult levels of total Ig-secreting cells reflected the smaller spleen size in immature birds, whereas the percentages of cells secreting Ig of each class were in the adult range by 31 days. By contrast, the numbers of cells recovered from the lungs of 50-day-old chickens were near the adult range, while the percentages of cells secreting either IgG, IgA, or IgM were much fewer than those seen in the lungs of adult chickens. These data indicate that the lungs of normal chickens are populated more slowly with Ig-secreting cells than either the bone marrow, spleen, or intestine. At all ages studied, greater numbers of Ig-secreting cells, particularly of the IgG and IgM classes, were recovered from the bone marrow and spleen as compared to the lungs and intestine. Since only a portion of the total bone marrow population was studied, these data include that the bone marrow may be a major site of Ig-secreting cells in chickens beginning shortly after hatching.

The effect of adrenaline and noradrenaline on coronary vascular reserve in the dog

1. Experiments were performed on dogs, anaesthetized with pentobarbitone sodium to measure the oxygen utilization of anterior ventricular wall. The anterior interventricular vein was used for venous blood collection and flow measurement. 2. Oxygen contents of arterial blood and coronary vein were measured. 3. Intravenous (femoral vein) adrenaline infusions raised arterial blood pressure and caused an initial fall in oxygen extraction from control values of 67-45%. Noradrenaline caused an initial fall from 67 to 51%. With both, the oxygen extraction began to rise during the infusion and continued, reaching maximum levels, (mean -82%) 10 min after start of infusion. The range of maximum values for oxygen extraction ratio after noradrenaline was 76-95%. 4. An inverse linear relation was established between blood pressure and oxygen extraction; whereas a direct linear relationship was established between coronary venous blood flow and mean arterial pressure. 5. When a change in blood pressure was prevented, the oxygen extraction ratio rose. 6. In all experiments, whether extraction rose or fell, the oxygen consumption rose. 7. It is suggested that oxygen extraction is a controlled variable and, with coronary blood flow, contributes quantitatively to coronary vascular reserve. 8. The tension-time index was not directly related to oxygen consumption in these experiments. Oxygen consumption rose in response to catecholamines by about the same amount even when mean arterial blood pressure was controlled. It is suggested that cardiac adjustments to altered afterload may also involve alterations in mechanical efficiency.

Critical closing and critical opening phenomena in the coronary vasculature of the dog

Direct measurements of coronary venous outflow in a right-heart bypass preparation were used to study the critical closing (CC) and critical opening (CO) phenomena in the anesthetized dog heart. Arterial pressure was lowered rapidly by hemorrhage, and CC pressure was the pressure at which coronary flow stopped completely. Shed blood was returned immediately or after 3 min of ischemia. The pressure at which coronary flow resumed (CO pressure) was measured. Coronary flow stopped at a mean aortic pressure of 14.3 mmHg. Vasodilator drugs and ischemic lowered CC pressure to 10.5 and 10.2 mmHg, respectively. Aortic pressure of 47.3 mmHg was needed to resume coronary flow following perfusion arrest. A brief period of ischemia did not significantly change the CO pressure. These results confirm the presence of CC phenomenon in dog heart and show that CC pressure can be altered by ischemia or vasodilators. It is suggested that the high value of CO pressure may be responsible for myocardial injury associated with ischemic cardiac arrest during open-heart surgery.

Function of the coronary arterial collateral network in healthy myocardium: studies of peripheral coronary pressure in the dog

Coronary collateral arterial network function was studied in normal dog myocardium using measurements of peripheral coronary pressure (pressure measured distal to a ligature in a branch of the anterior descending coronary artery). Free communication between all parts of the anastomotic network was demonstrated. Adrenaline infusion raised systolic and diastolic levels of peripheral coronary pressure both when the systemic blood pressure was allowed to rise and in experiments where rise in systemic arterial pressure was prevented by haemorrhage. It is suggested that myocardial contraction pressurizes the subendocardial network thus facilitating perfusion of postnetwork vessels. This effect prolongs the time during which coronary vessels affected by rising intramyocardial pressure in systole can be perfused during the cardiac cycle. Additional evidence is presented to indicate the existence of a critical closing pressure in the coronary circulation at about 1.7 kPa (12.8 mmHg).

Blood Perfusion Measurements by the Analysis of the Heated Thermocouple Probe’s Temperature Transients

The Gibbs’ heated thermocouple technique for measuring a tissue’s thermal conductivity to infer the blood perfusion rate has been synthesized with a model of transient heal transport in perfused tissue. This procedure eliminates the necessity of probe calibration in surrogate tissue. The analytical predictions of the transient temperature behavior of a newly designed spherical probe were compared with experimental temperature transients to deduce thermal conductivities of and perfusion rates in gelatin and dog kidney. The principle heating modality was step heating. Consistent conductivity values for both the gelatin and the kidney were found. The calculated perfusion rates in the kidney were consistent but were higly dependent upon probe size and geometry, and the independently measured tissue’s thermal conductivity.

Effect of a local cold stress on peripheral temperatures of Inuit, Oriental, and Caucasian subjects

Male subjects comprised of six Inuit from Igloolik, N.W.T., and five Orientals and six Caucasians from Toronto, Ont., volunteered for tests to determine the effect of localized cold stress on peripheral temperatures. In each subject, skin temperatures of the right index finger, the arm, and the cheek, as well as blood pressure and heart rate, were measured before, during, and after foot immersion in water of 10 degrees C temperature for 10 min. There was an immediate decrease in finger temperature on foot immersion in all three subject groups; however, the Inuit finger temperatures recovered very quickly to control values, the Caucasian finger temperatures began to increase after decreasing for 7.5 min, and the Oriental finger temperatures decreased continuously during the foot immersion and remained cool even 10 min after the removal of the cold stimulus. The cold stimulus did not affect the cheek or arm temperatures of any of the groups. In all subjects, systolic and diastolic blood pressures and heart rates increased on foot immersion, gradually returning towards normal values. No intergroup differences were seen in these parameters.

Effect of alterations in ambient temperature on blood flow in the skin

The effect of changing ambient temperature on skin temperature was recorded in human subjects; also, its effect on blood flow was measured using venous occlusion and optical plethysmography. When cold stimulus was removed in stages using a heating cabinet, it was found that a biphasic flow response occurred in the fingers with each step change in temperature. There was a rapid transient rise followed by a decline to an equilibrium flow level. The transient rise occurred even when the temperature rose from 37 to 40 degrees C, although at this level the equilibrium remained unchanged. It is suggested that the transient rise was due to stimulation of Hensel's dynamic warmth receptors, whereas the rise in equilibrium temperature was due to removal of cold stimulus, which at low ambient temperatures maintains reflex vasoconstriction through activation of static cold receptors. Upper arm skin responded to removal of cold stimulus by a fall in temperature. Immersion of a different limb in cold water produced vasoconstriction in fingers but vasodilatation in the upper arm skin. It is suggested that this may be due to neurogenic vasodilatation, though the present work gives no indication as to pathways.

Dynamics of myocardial infarction--the role of critical closing pressure

Pressure in the primary distributing network of a vessel on the surface of the heart is normally sufficient to prevent critical closure of its derivative vessels. It is proposed that acute occlusion of a major supply vessel or over activity of the heart in the presence of an impairment of the lumen of a major supply vessel may reduce transmural pressure in parts of the network. In consequence vasospasm, the result directly of critical closure, is postulated as the basis for myocardial infarction, together with maximal dilatation of vessels in which pressure did not fall to critical levels.

The action of nitroglycerine and dipyridamole in normal and ischaemic dog heart

1 Network and post-network resistances were measured together with heat clearance and heat production in the myocardium. 2 Nitroglycerine dilated all resistance vessels but was twice as effective on network as compared with post-network vessels. 3 Dipyridamole dilated network and post-network vessels equally. 4 Nitroglycerine had no effect on heat clearance or heat production in ischaemic myocardium. 5 Dipyridamole increased heat clearance in normal but not in ischaemic myocardium. 6 Dipyridamole depressed heat production in normal and ischaemic myocardium. 7 That the clinical effectiveness of nitroglycerine does not depend entirely on its coronary vasodilator properties is confirmed. 8 It is suggested that the action of dipyridamole in depressing myocardial heat production may be due to an action on the efficiency of oxygen utilization during cardiac contraction.