Cloud feedback: a stabilizing effect for the early Earth?

The effect of variations in cloud cover, optical properties, and fractional distribution with altitude on the mean surface temperature of a model of the early earth has been investigated. In all cases examined, cloud-climate feedbacks result in temperatures greater than those in models with no cloud feedbacks. If the model of hydrospheric feedback effects is correct, then cloud feedbacks are as important to the climate as changes in solar luminosity and atmospheric composition during the earth's atmospheric evolution. In particular, the early earth need not become completely ice-covered if strong negative cloud feedbacks occur. However, until a proper understanding of cloud feedbacks is available, conclusions regarding conditions in the early atmosphere must remain in doubt.

Subcortical profile of memory compromise among HIV-1-infected individuals.

OBJECTIVE: To examine the hypothesis of subcortical pathologic impairment in HIV/AIDS. METHOD: The study included 22 HIV+, 22 HIV- controls, 22 learning disordered (LD) HIV-, and 22 depressive HIV-. The groups were compared on eight WMS-III Indices. RESULTS: Analyses revealed significantly lower scores (p < .05) in HIV+ on visual immediate memory, immediate memory, visual delayed memory, auditory delayed memory, working memory, and general memory. For all cases, HIV+ participants scored below the control group only. CONCLUSIONS: WMS-III indices discriminated HIV+ participants from normal comparisons. Inability to find differences between HIV+ and depressive and LD groups reflects the isolation of the subcortical effect to the HIV+ group.

The detection and characterisation of collagenase inhibitors from rabbit tissues in culture.

As tissue cultures, rabbit bone, skin and non-gravid uterus synthesise inhibitors of collagenase (EC 3.4.24.3). An assay for the inhibitors is described and their action on collagenase from different tissue sources demonstrated. Evidence for the involvement of the tissue inhibitors of collagenase in the latency of the enzyme in culture media is presented. Latent collagenase was activated by treatment with 4-aminophenylmercuric acetate, and then reacted with the inhibitors to form inactive complexes with properties similar to the naturally occurring latent enzyme forms. The associated changes in molecular weight are detailed, and discussed in relation to the observations of other workers concerning the extracellular control of collagenase activity.

Atrial myxoma with multiple myeloma.

A male patient was observed for seven years, from the onset of neurologic symptoms to removal of a left atrial myxoma. Mild broad-based elevation of the serum gamma-globulin level with a normal bone marrow aspirate was seen early in the course of disease. The broad-based gamma-globulin level increased, and at the time of surgical removal of the tumor, the patient was found to have a monoclonal increase of K light chain IgG with 60% infiltration of the bone with immature plasma cells. The findings are consistent with the view that continuous immunologic stimulation by products of the atrial tumor resulted in malignant transformation of immunocytes with resulting IgG multiple myeloma.

Calciphylaxis in man. A syndrome of tissue necrosis and vascular calcification in 11 patients with chronic renal failure.

Eleven patients with chronic renal failure and presumed secondary hyperparathyroidism developed a syndrome of medial calcinosis of the arteries and painful ischemic ulcers of the fingers, legs, or thighs, or any combination of the three. Five patients required maintenance hemodialysis; six had functioning renal homografts. Severe hyperphosphatemia had existed in each; seven showed roentgenographic evidence of subperiosteal resorption. Similarities are evident between the lesions and experimentally produced calciphylaxix. The lesions demonstrated a relentless, progressive course, with serious morbidity and mortality. Hyperplastic or adenomatours parathyroid tissue was removed from ten of 11 patients unergoing surgical procedures; healing followed in seven patients. Treatment with phosphate-binding antacids to lower serum phosphorus levels may prevent this syndrome. Total or subtotal parathyroidectomy should be considered when ischemic skin lesions appear in uremic patients or in renal transplant recipients.

Activation of BKCa channels in acutely dissociated neurones from the rat ventromedial hypothalamus by NS 1619.

NS 1619 activates the large-conductance Ca(2+)-dependent K+ channel (BKCa) in membrane patches isolated from rat ventromedial hypothalamic neurones. The activation is concentration dependent, with a maximal effect at less than 30 microM, reversible and can be inhibited by application of iberiotoxin to the extracellular membrane. NS 1619 does not activate ATP-K+ channels present in the same neurones.

Lack of effect of potassium channel openers on ATP-modulated potassium channels recorded from rat ventromedial hypothalamic neurones.

1. Single neuronal cells were freshly isolated from the ventromedial hypothalamic nuclei (VMHN) of the rat brain. Currents through ATP-modulated and large conductance (160 and 250 pS) calcium-activated potassium channels were recorded by the cell-attached and excised inside-out patch techniques. 2. BRL38227 (lemakalim; 30-90 microM) applied to the superfusing medium produced no change in firing rate of isolated glucose-receptive VMHN neurones in cell-attached recordings. 3. BRL38227, at concentrations of between 30-100 microM applied to the intracellular (cytoplasmic) aspect of inside-out patches, had no effect on the activity of ATP-sensitive K+ channels in the absence of ATP or in the presence of a sub-maximal inhibitory concentration (3 mM) of ATP. Cromakalim, pinacidil, minoxidil sulphate and diazoxide also produced no effect under these conditions. 4. The potassium channel openers (KCO's) were tested on ATP-activated potassium channels recorded from a further subpopulation of VMHN neurones. Application of BRL38227 (up to and including 100 microM) to this channel in inside-out patches either in the absence of ATP or when activated by 5 mM ATP had no effect on channel activity. Identical results were obtained with cromakalim and pinacidil. 5. BRL38227 had no effect on either of the large conductance (250 pS and 160 pS) calcium-activated potassium channels in VMHN neurones. 6. Intracellular recordings were made from glucose-receptive VMHN neurones in rat brain slices. Cromakalim (50 microM) or diazoxide (60 microM) did not alter the firing rate or passive membrane properties of these neurones demonstrated to be sensitive to tolbutamide (0.1 mM). 7. These results show that the KCO's tested in this study have no effect either on VMHN neurones contained in brain slices or on the activity of any of the ATP-modulated potassium channels under isolated patch conditions associated with these neurones.

Phosphinic acid analogues of GABA are antagonists at the GABAB receptor in the rat anococcygeus.

CGP 35348 (3-aminopropyl(diethoxymethyl)phosphinic acid) and 3-aminopropyl(n-hexyl)phosphinic acid (3-APHPA) were tested in the rat anococcygeus muscle against CGP 27492 (3-aminopropylphosphinic acid), a selective GABAB agonist, for their antagonist activity. Their antagonist potency was compared with that of 2-hydroxysaclofen. The pA2 values for CGP 35348, 3-APHPA and 2-hydroxysaclofen were 5.38, 4.86, 4.45 respectively in the rat anococcygeus muscle. These results confirm the previous reports of GABAB antagonist activity for these compounds and show a marginal improvement in potency over 2-hydroxysaclofen.

Review of large intestinal motility and mechanisms of impaction in the horse.

The large intestine has distinct motility patterns which include non-rhythmic haustral kneading of ingesta and stronger rhythmic retropulsive and propulsive contractions which move ingesta along the tract. A variable site electrical pacemaker exists at the pelvic flexure where the strong rhythmic contractions begin. The large intestine can contract adequately with only the intrinsic nerve supply intact. Neurotransmitters have profound effects on large intestinal activity.

Distribution of substance P-like immunoreactivity in the enteric neurons of the large colon of normal and amitraz-treated ponies: an immunocytochemical study.

The distribution of the putative motor excitatory neurotransmitter, substance P, was studied immunocytochemically in the left dorsal colon of four normal control ponies and three ponies with amitraz-induced impaction colic. Substance P-like immunoreactivity in the control ponies was observed in nerve fibres in all layers of the bowel wall and in the nerve cell bodies of the enteric ganglia. The substance P-like immunoreactivity was clearly more intense in the cell bodies of submucosal ganglia than in those of the myenteric ganglia. The internodal nerve strands of the myenteric plexus were very rich in substance P-like immunoreactivity and within the ganglia they formed dense varicose networks around the neuronal cell bodies. Nerve bundles rich in substance P-like immunoreactivity diverged inward from the myenteric plexus to contribute an abundance of varicose immunoreactive fibres to the circular muscle of the tunica muscularis. Nerve fascicles with substance P-like immunoreactivity were sparse in the longitudinal muscle except in the thickened taenial band. In the submucosa many of the nerve fibres with substance P-like immunoreactivity appeared to arise from ganglionic cell bodies. Immunoreactive fibres commonly condensed around arterial vessels in the submucosa. Fine immunoreactive nerve fascicles from the submucosal plexus also projected internally to supply the muscularis mucosae and form periglandular arrays in the lamina propria. The distribution of substance P-like immunoreactivity in the normal equine colon differed in some respects from patterns observed in large intestines of other mammals. When the colons of normal and amitraz-treated ponies were compared no differences were discerned in the distribution or intensity of substance P-like reactivity.

A comparison of psychological/psychiatric symptomatology of women and men sexually abused as children.

OBJECTIVE: The purpose of this study was to explore gender differences in symptomatology among sexual abuse survivors utilizing a standardized measure of specific symptom patterns, the Symptom Checklist 90-Revised (SCL-90-R). METHOD: Gender differences in symptomatology of adults sexually victimized as children were examined. Participants were 162 women and 25 men entering an outpatient treatment program for adult survivors of childhood sexual abuse (CSA) in a university-based community mental health center. Symptomatology was measured using the Symptom Checklist 90-Revised (SCL-90-R). RESULTS: Although no differences appeared when examining the raw data, the results changed dramatically once the data were converted into T-scores and epidemiological SCL-90-R gender differences were taken into account. The findings indicate that men exhibited significantly more interpersonal sensitivity, depression, anxiety, and phobic anxiety than women in relation to their respective normative samples. CONCLUSIONS: The use of nonclinical T-scores in this study allows for the interpretation that men survivors of childhood sexual abuse (CSA) have higher levels of symptomatology than women survivors when compared to their respective normative samples.

Equine colonic motility: interactions among wall motion, propulsion, and fluid flow.

Transmission of intestinal content with respect to wall position and intraluminal pressure was studied using implanted catheters in portions of the haustrated left ventral colon and nonhaustrated pelvic flexure and left dorsal colon in 3 conscious, standing, and feeding ponies. Wall position and content movement was studied in 1 noncatheterized conscious pony that was standing and eating. When coordinated wall movements involving greater than or equal to 30 cm of adjacent colon were seen, point-to-point content movement accompanied intraluminal pressure peaks occurring in the same direction. Near the pelvic flexure, intraluminal pressure peak maximums coincided and reduced colonic diameters and reduced intercatheter distances. Qualitative observation of 3 related aspects of intestinal motility: wall motion, propulsion, and fluid movement can be studied in the conscious feeding pony.

Normal motility of the cecum and right ventral colon in ponies.

To study the normal motility of the cecum and right ventral colon (RVC) in 3 mature Shetland ponies, a 6-part, indwelling, intraluminal catheter system was used to measure intraluminal pressure changes. Three catheters were placed in the cecum at 10, 25, and 40 cm from the cecocolic orifice, and 3 catheters were placed in the RVC at 10, 20, and 30 cm from the cecocolic orifice. Recordings were made during the interdigestive period beginning 2 weeks after surgical operation was done. Frequent, low-amplitude peaks (0.35 +/- 0.13 coordinated peaks/min) were seen involving the cecal body and caudal cecal base, which represented a haustra-to-haustra mixing pattern. Coordinated pressure peaks originated in the cecal body and progressed to the cranial cecal base (0.07 +/- 0.01/min) or originated in the cranial cecal base and progressed to the cecal body (0.07 +/- 0.04/min). Associated with a loud rush of ingesta heard on transabdominal auscultation and progression of liquid ingesta confirmed with barium contrast radiography, there was a series of coordinated, progressive pressure peaks which originated in the cecal body, sequentially involved the cecal base, traversed the cecocolic orifice, and extended into the RVC (0.36 +/- 0.05/min). It seemed that a pacemaker region existed in the cecal body and initiated the important aborally propagated progressive pattern responsible for the transit of ingesta from the cecum to the RVC. A separate mechanism for the transit of gas was not identified. In the RVC, infrequent, nondirectional, low-amplitude segmental pressure peaks (0.12 +/- 0.06/min), and aborally progressive coordinated pressure peaks originating at the beginning of the RVC (0.09 +/- 0.02/min), occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Retropulsion-propulsion in equine large colon.

The circular and longitudinal muscle coats of equine "midcolon" were found to be directly electrically coupled. They appear to act in concert, in healthy animals, as a pacemaker in the area of the large colon pelvic flexure, for retropulsive-propulsive myoelectrical events. The retropulsive events keep the cecum and right ventral and left ventral divisions of the colon filled, imposing a delay time for fermentation of cellulose and for bacterial protein synthesis. Point-to-point involvement of adjacent colon sections was slowed by cooling the intestinal contents with no adverse clinical signs. Diminution of the blood flow to this regulatory area was achieved in 12 weanling foals (raised parasite-free) by parasitic cranial mesenteric arteritis, using Strongylus vulgaris larvae. Four of the 12 developed clinical signs of abdominal pain, but on necropsy 3 of these 4 had no gross lesions in the gastrointestinal tract. Dissociation of the left ventral and left dorsal colon divisions, as regards intraluminal pressure events and their antecedent myoelectrical action potentials, was induced in 7 of 8 adult animals given an acaricide which under field conditions is associated with progressive large colon obstruction and colic.

The detection of malingered posttraumatic stress disorder with MMPI-2 fake bad indices.

This investigation explored the effect of posttraumatic stress disorder (PTSD) simulation on Minnesota Multiphasic Personality Inventory-2 (MMPI-2) responses, to detect malingered from genuine PTSD. Sixty-four adult PTSD outpatients at a child sexual abuse (CSA) survivor treatment program were compared with 85 adult college students instructed and trained to malinger PTSD. MMPI-2 overreporting indices examined were F, F-Fb, F-K, F(p), Ds2, O-S, OT, and FBS. A stepwise discriminant analysis identified F(p), F-K, and O-S as the best malingering predictors. A predictive discriminant analysis yielded good hit rates for the model, with impressive cross-validation results. Cutoff scores were assessed for the model's predictors. Clinical implications for detecting malingered PTSD using the MMPI-2 are discussed.

Ground based radon-222 observations and their application to atmospheric studies.

The aim of this paper is to review recent trends in the application of ground based radon observations to atmospheric research. In spite of over four decades of atmospheric radon monitoring, only in the past decade has the potential of this passive tracer been realised through a series of atmospheric model evaluation studies. Firstly, the key operational requirements for baseline radon detectors are briefly discussed, including lower limit of detection and response time. Then, current radon-related benchmarks for the evaluation of regional and global models are reviewed, with particular consideration given to the implications of data availability, resolution, site location and model spatial/temporal resolution. An 8-year subset of radon observations from the Cape Grim Baseline Air Pollution Station is used to suggest new benchmarks that exploit long-term data sets. Lastly an overview is presented of a technique that uses radon to estimate regional fluxes of climatically sensitive gases, with specific examples for CO2, CH4 and N2O.

Assessment of visual-motor coordination in 6- to 11-yr.-olds.

The concurrent and content validity of the Rey-Osterrieth Complex Figure Test and the Beery Developmental Test of Visual-Motor Integration-Third Revision were investigated through correlational analysis. 432 children, ages 6 to 11 years, were administered both tests. Across age groups participants performed better on both measures, providing support for the similarity of the measures and their sensitivity to the development of visuomotor integration. Although analysis indicated considerable overlap in the content of the two scales, the shared variance ranged from 7% to 31%, depending on the age of the child. The Rey-Osterrieth figure is composed of overlapping squares, rectangles, triangles, and various other shapes. Given this complex combination, scores on this test reflect the examinees' visual organization and motor planning skills. On the other hand, the Beery test consists of a series of shapes which progress from simple figures to more complex ones. Because the figures become more difficult to copy, the score on this test reflects the examinees' developmental level of visuomotor ability. Despite these differences in test stimuli and interpretation of performance, the present study showed considerable shared variance in the scores of the examinees who took both tests. Finally, local norms for the Rey-Osterrieth figure using the scoring approach of E. M. Taylor (1959, adapted from Osterrieth, 1944) and including standard scores are presented for children ages 6 to 11 years.

Advancing from flexible sigmoidoscopy to colonoscopy in rural family practice.

This paper describes the background, experience, training, and preceptorship of a rural family physician that culminated in provision of diagnostic and therapeutic colonoscopy to his patients. Initial training took place in a two-day continuing medical education course. Subsequent training consisted of one-on-one training in 11 colonoscopies and five polypectomies, correspondence, recommended readings, a one-on-one preceptorship, and telephone consultation. Training was provided by University of Tennessee faculty who were experts in the area of colonoscopy and polypectomy procedures. The outcomes of 250 consecutive colonoscopies performed by the rural family physician are documented here. Training requirements vary widely by professional organization and subspecialty. Some subspecialists have recommended as many as 100 supervised colonoscopies and 25 polypectomies as a minimum training requirement for hospital privileges. It is our contention that unnecessarily high training requirements add to educational costs and may restrict qualified rural physicians from providing these services.