The inconstancy of the transient climate response parameter under increasing CO2

In the Coupled Model Intercomparison Project Phase 5 (CMIP5), the model-mean increase in global mean surface air temperature T under the 1pctCO2 scenario (atmospheric CO(2) increasing at 1% yr(-1)) during the second doubling of CO(2) is 40% larger than the transient climate response (TCR), i.e. the increase in T during the first doubling. We identify four possible contributory effects. First, the surface climate system loses heat less readily into the ocean beneath as the latter warms. The model spread in the thermal coupling between the upper and deep ocean largely explains the model spread in ocean heat uptake efficiency. Second, CO(2) radiative forcing may rise more rapidly than logarithmically with CO(2) concentration. Third, the climate feedback parameter may decline as the CO(2) concentration rises. With CMIP5 data, we cannot distinguish the second and third possibilities. Fourth, the climate feedback parameter declines as time passes or T rises; in 1pctCO2, this effect is less important than the others. We find that T projected for the end of the twenty-first century correlates more highly with T at the time of quadrupled CO(2) in 1pctCO2 than with the TCR, and we suggest that the TCR may be underestimated from observed climate change.

Bile acid and inflammation activate gastric cardia stem cells in a mouse model of Barrett-like metaplasia

Esophageal adenocarcinoma (EAC) arises from Barrett esophagus (BE), intestinal-like columnar metaplasia linked to reflux esophagitis. In a transgenic mouse model of BE, esophageal overexpression of interleukin-1β phenocopies human pathology with evolution of esophagitis, Barrett-like metaplasia and EAC. Histopathology and gene signatures closely resembled human BE, with upregulation of TFF2, Bmp4, Cdx2, Notch1, and IL-6. The development of BE and EAC was accelerated by exposure to bile acids and/or nitrosamines, and inhibited by IL-6 deficiency. Lgr5(+) gastric cardia stem cells present in BE were able to lineage trace the early BE lesion. Our data suggest that BE and EAC arise from gastric progenitors due to a tumor-promoting IL-1β-IL-6 signaling cascade and Dll1-dependent Notch signaling.

Bri2-23 is a potential cerebrospinal fluid biomarker in multiple sclerosis

To identify potential multiple sclerosis (MS)-specific biomarkers, we used a proteomic approach to screen cerebrospinal fluid (CSF) from 40 MS patients and 13 controls. We identified seven proteins (Beta-2-microglobulin, Bri2-23, Fetuin-A, Kallikrein-6, Plasminogen, Ribonuclease-1, and Transferrin) that had significantly altered levels in MS compared to controls. Clinical subgroup analysis revealed that decreased CSF levels of Bri2-23, a peptide cleaved from Bri2, were significantly associated with patients having cerebellar dysfunction and cognition impairment. Furthermore, expression levels of Bri2 were specifically decreased in the cerebellum compared to other areas of same brain in MS but not in controls, suggesting that decreased cerebellar Bri2 expression may play a role in cerebellar dysfunction. The association with cognition impairment is also of interest because Bri2 is linked to the amyloid processing pathway in the brain. CSF levels of Bri2-23 may serve as a biomarker of these functions in MS and merits further investigation.

Prioritising drugs for single patient (n-of-1) trials in palliative care

Many of the drugs prescribed commonly to palliative care patients have potentially significant side-effects and are of unproven benefit. The acquisition of evidence to support the prescribing of these drugs has been very slow. Single patient trials (SPTs) (also known as n-of-1 trials) offer a potential means of obtaining the evidence necessary to support or refute the use of several of the drugs and interventions whose use is currently based on physician experience or anecdote alone. A list of SPTs considered "most urgent", for commonly employed treatments and for the most common and most troublesome symptoms in palliative care is presented. These are drugs for which the gap between evidence and practice is greatest, where the evidence of efficacy is most lacking, where significant side effects potentially lead to the greatest morbidity, or where cost is a major patient burden. Although not all the drugs used in palliative care are suitable, SPTs provide a potential alternative method of gathering evidence in palliative care.

Intranasal sufentanil for cancer-associated breakthrough pain

The objective of this study was to demonstrate the efficacy, safety and patient acceptability of the use of intranasal sufentanil for cancer-associated breakthrough pain. This was a prospective, open label, observational study of patients in three inpatient palliative care units in Australia. Patients on opioids with cancer-associated breakthrough pain and clinical evidence of opioid responsiveness to their breakthrough pain were given intranasal (IN) Sufentanil via a GO Medical patient controlled IN analgesia device. The main outcome measures were pain scores, need to revert to previous breakthrough opioid after 30 min, number of patients who chose to continue using IN sufentanil, and adverse effects. There were 64 episodes of use of IN sufentanil for breakthrough pain in 30 patients. There was a significant reduction in pain scores at 15 (P < 0.0001) and 30 min (P < 0.0001). In only 4/64 (6%) episodes of breakthrough pain did the participants choose to revert to their prestudy breakthrough medication. Twenty-three patients (77%) rated IN sufentanil as better than their prestudy breakthrough medication. The incidence of adverse effects was low and most were mild. Our study showed that IN sufentanil can provide relatively rapid onset, intense but relatively short lasting analgesia and in the palliative care setting it is an effective, practical, and safe option for breakthrough pain.

Medically assisted hydration for palliative care patients

BACKGROUND

Many palliative care patients have reduced oral intake during their illness. The management of this can include the provision of medically assisted hydration with the aim of prolonging the length of life of a patient, improving their quality of life, or both.

OBJECTIVES

To determine the effect of medically assisted hydration in palliative care patients on their quality and length of life.

SEARCH STRATEGY

Studies were identified from searching CENTRAL, MEDLINE (1966 to 2008), EMBASE (1980 to 2008), CINAHL, CANCERLIT, Caresearch, Dissertation abstracts, SCIENCE CITATION INDEX and the reference lists of all eligible studies, key textbooks, and previous systematic reviews. The date of the latest search was February 2008.

SELECTION CRITERIA

All relevant randomised controlled trials (RCTs) or prospective controlled studies of medically assisted hydration in palliative care patients.

DATA COLLECTION AND ANALYSIS

Five relevant studies were identified. These included two RCTs (93 participants), and three prospective controlled trials (360 participants). These were assessed independently by two review authors for quality and validity. The small number of studies and the heterogeneity of the data meant that a quantitative analysis was not possible, so a description of the main findings was included only.

MAIN RESULTS

One study found that sedation and myoclonus (involuntary contractions of muscles) were improved more in the intervention group (28 - hydration, 23 - placebo). Another study found that dehydration was significantly higher in the non-hydration group, but that some fluid retention symptoms (pleural effusion, peripheral oedema and ascites) were significantly higher in the hydration group (59 - hydration group, 167 - non -hydration group). The other three studies did not show significant differences in outcomes between the two groups.

AUTHORS' CONCLUSIONS

There are insufficient good quality studies to make any recommendations for practice with regard to the use of medically assisted hydration in palliative care patients.

Neuropathic pain: are we out of the woods yet?

Patients suffering from neuropathic pain continue to pose challenges in clinical practice. This descriptive review discusses the continuing debate on the definition and concerns about increasing incidence of neuropathic pain. The clinical features of neuropathic pain are outlined, and the current understanding of the possible mechanisms of neuropathic pain is highlighted. Current management strategies are reviewed, and future advances in our understanding of the mechanisms, accurate clinical diagnosis and more effective treatment strategies are eagerly awaited.

Does use of isotretinoin rule out a career in flying?

AIM

To evaluate whether previous isotretinoin use induces permanent, measurable, and clinically significant abnormalities in night vision such that flying is precluded, and whether potential military and civilian commercial aviators should be screened routinely.

METHODS

A retrospective, non-interventional, consecutive case series of 47 individuals with a confirmed history of oral isotretinoin use were compared to 20 age and sex matched controls.

RESULTS

47 individuals (44 males and three females), age range 17-33, underwent Goldmann-Weekers dark adaptation (DA) and standard electroretinogram (ERG) according to ISCEV protocols. 34 patients showed no abnormality in any parameters. Two patients had abnormal DA and ERGs. The mean scotopic ERG b wave amplitude of the isotretinoin group was 496.5 microV (SD 51.3 microV) compared with 501.7 microV (62.3.1 microV) among the controls. The group mean a:b ratio was 0.55 (0.04) compared to 0.69 (0.08) in the controls.

CONCLUSION

Previous use of isotretinoin may have caused retinal toxicity in two subjects and laboratory evidence of night blindness in 11 further subjects. One subject had subclinical changes remaining in the ERG 96 months after cessation of isotretinoin. This may justify the directed use of electrophysiological screening in professions that are night vision critical.

Prospective audit of short-term concurrent ketamine, opioid and anti-inflammatory (‘triple-agent’) therapy for episodes of acute on chronic pain

AIM

This prospective audit was undertaken in order to document the analgesic response and adverse effects of concurrent short-term ('burst') triple-agent analgesic (ketamine, an opioid and an anti-inflammatory agent--either steroidal or non-steroidal) administration, for episodes of acute on chronic pain. The clinical hypothesis in this study is that better pain control may be obtained by simultaneous multiple target receptor blockade.

METHOD

The response of 18 patients is reported. The pain and analgesic requirement data for the 24 h before starting triple-agent therapy were compared with the last 24 h on the triple-agent therapy. Patients were then classified as responders or non-responders.

RESULTS

According to stringent clinical criteria, 12 out of the 18 patients were classified as responders. The response rate was highest for somatic pain (7/9) and appeared to decrease with duration of prior uncontrolled pain. Only four out of the 18 patients reported adverse effects and all of these were minor.

CONCLUSIONS

The results suggest that this 'burst' triple-agent approach is safe and effective in an inpatient palliative care population during episodes of poorly controlled acute on chronic pain, and warrants further investigation to ascertain whether it gives superior results compared to the 'gold-standard' WHO ladder approach.

Biometry of the silicone oil-filled eye: II

PURPOSE

In phakic silicone oil-filled eyes, removal of the silicone oil can be combined with phacoemulsification and intraocular lens (IOL) implantation. True axial length (AL) of the silicone oil-filled (viscosity 1300 centistokes) eye can be estimated from the measured AL (MAL) obtained on A and/or B scan echography, by multiplying MAL by a conversion factor of 0.71. IOL power can then be calculated using current biometry formulae (SRK/T). This study aims to evaluate the conversion factor in clinical practice.

METHODS

Eleven patients undergoing combined removal of silicone oil and phacoemulsification with IOL implant were studied. Patients were divided into two groups. In Group 1 (seven patients), the IOL was placed in the capsular bag and in Group 2 (four patients) the IOL was placed in the ciliary sulcus. Calculated AL (CAL) was obtained by multiplying the MAL of the silicone oil-filled eye (as measured on A or B scan ultrasonagraphy) by the conversion factor of 0.71. IOL power was then estimated using the CAL in the SRK/T formula. The spherical equivalent of the postoperative refractive error was compared to predicted refractive error.

RESULTS

The mean difference in actual and predicted refractive error was 0.74 dioptres (D) (standard deviation 0.75 D) for Group 1 and 1.31 D (standard deviation 1.4 D) for Group 2.

CONCLUSIONS

The conversion factor of 0.71 corrects for the apparent increase in AL induced by silicone oil of viscosity 1300 centistokes. This allows accurate prediction of the required IOL power in eyes undergoing combined cataract extraction, removal of silicone oil and lens implant. Sulcus placement of the IOL gives a less predictable result than placement in the capsular bag.

Inpatient palliative medicine is evidence based

Specialist palliative care services have previously been studied to see whether their intervention is of benefit. However, there is a lack of data on whether interventions in individual palliative care units are evidence based. This study looked at 32 problems and 114 interventions over 1 month in January 2000 in an inpatient palliative care unit. These interventions were then researched to see if there had been trials showing their benefit. The results were then classified: 81% were evidence based (randomized controlled trials 48%, evidence from other trials 27%, convincing non-experimental evidence 6%). This compares favourably with studies performed in other areas of medicine.

Micro syndrome in Muslim Pakistan children

OBJECTIVE

To date, Micro syndrome has been reported in only three children from one family. We describe an additional 14 children from 11 families.

DESIGN

Retrospective case series.

PARTICIPANTS

Fourteen children from 11 families attending one of five British hospitals.

MAIN OUTCOME MEASURES

The following features were documented: pre- and postoperative eye findings, electrophysiologic analysis, systemic abnormalities, development, neuroimaging, genealogy, geographic origin of family.

RESULTS

We expand and modify the description of ocular and electrophysiologic findings in Micro syndrome. The eye findings of microphakia, microphthalmos, characteristic lens opacity, and atonic pupils were the presenting feature in all infants and were the most reliable diagnostic signs in the immediate postnatal period. Cortical visual impairment, microcephaly, and developmental delay were not always detectable initially; they developed in all children by 6 months of age. Microgenitalia were a useful diagnostic clue in affected males only. Therefore, eye features were more consistently useful in determining diagnosis than dysmorphology or brain imaging. The families of all the children originate from the Muslim population of Northern Pakistan. Inheritance is likely to be autosomal recessive.

CONCLUSIONS

Micro syndrome usually presents to the ophthalmologist, who may be able to make the diagnosis on the basis of characteristic eye findings combined with ethnic origin. Initially, the nature and severity of nonophthalmic features are not apparent. Early diagnosis of the underlying condition is important to guide management of the cataracts, glaucoma, and developmental delay. It is helpful for the family and medical staff to be aware of the low level of vision that develops despite optimal ophthalmic intervention. Genetic counseling extending into the wider family is particularly important in view of the high rate of consanguinity.

Targeted deletion of the Vgf gene indicates that the encoded secretory peptide precursor plays a novel role in the regulation of energy balance

To determine the function of VGF, a secreted polypeptide that is synthesized by neurons, is abundant in the hypothalamus, and is regulated in the brain by electrical activity, injury, and the circadian clock, we generated knockout mice lacking Vgf. Homozygous mutants are small, hypermetabolic, hyperactive, and infertile, with markedly reduced leptin levels and fat stores and altered hypothalamic proopiomelanocortin (POMC), neuropeptide Y (NPY), and agouti-related peptide (AGRP) expression. Furthermore, VGF mRNA synthesis is induced in the hypothalamic arcuate nuclei of fasted normal mice. VGF therefore plays a critical role in the regulation of energy homeostasis, suggesting that the study of lean VGF mutant mice may provide insight into wasting disorders and, moreover, that pharmacological antagonism of VGF action(s) might constitute the basis for treatment of obesity.

Biometry of the silicone oil-filled eye

PURPOSE

The advent of silicone oil tamponade has resulted in improved success rates in complicated retinal detachment surgery. Its use, however, can induce cataract formation in phakic eyes. In selected patients, removal of silicone oil can be combined with phacoemulsification of the cataract and intraocular lens (IOL) implantation, thus avoiding a further operation. This, however, poses a problem when trying to decide the power of IOL to be used, since the echographically measured axial length (AL) of an eye is greater in the presence of silicone oil. We performed ultrasound examination in the presence of silicone oil of viscosity 1300 centistokes, in order to determine whether the measured AL varied from the true AL by a constant factor.

METHODS

The ALs of 7 phakic eyes were measured by A-mode echography, with and without silicone oil of viscosity 1300 centistokes in the posterior segment. The retina was attached in all cases. The control group consisted of 6 phakic eyes with attached retinae undergoing vitrectomy without the use of silicone oil. The ALs in the control group were measured before and after vitrectomy.

RESULTS

The mean ratio of true AL to measured AL in the presence of silicone oil was 0.71 (standard deviation 0.01; range 0.70-0.73; median 0.71) in the 7 eyes in this study. In the control group, vitrectomy appeared to have no significant effect on AL.

CONCLUSIONS

We have established a constant which corrects for the apparent increase in AL induced by silicone oil of viscosity 1300 centistokes. This conversion factor, when used in existing biometry formulae (SRK/T), allows estimation of the power of IOL required in eyes undergoing combined cataract extraction, removal of silicone oil and lens implantation.

A cluster of equine granulomatous enteritis cases: the link with aluminium

A cluster of 6 cases of equine granulomatous enteritis is described. Aluminium was demonstrated in the tissues and lesions of these horses and in the intimal bodies of intestinal vessels. The relationship between granulomatous lesions, aluminium, acidity and invading microorganisms, particularly parasites, is presented and discussed.

The expression cassette determines the functional activity of ribozymes in mammalian cells by controlling their intracellular localization

In order to better understand the influence of RNA transcript context on RNA localization and catalytic RNA efficacy in vivo, we have constructed and characterized several expression cassettes useful for transcribing short RNAs with well defined 5' and 3' appended flanking sequences. These cassettes contain promoter sequences from the human U1 snRNA, U6 snRNA, or tRNA Meti genes, fused to various processing/stabilizing sequences. The levels of expression and the sub-cellular localization of the resulting RNAs were determined and compared with those obtained from Pol II promoters normally linked to mRNA production, which include a cap and polyadenylation signal. The tRNA, Ul, and U6 transcripts were nuclear in localization and expressed at the highest levels, while the standard Pol II promoted transcripts were cytoplasmic and present at lower levels. The ability of these cassettes to confer ribozyme activity in vivo was tested with two assays. First, an SIV-growth hormone reporter gene was transiently transfected into human embryonic kidney cells expressing an anti-SIV ribozyme. Second, cultured T lymphocytes expressing an anti-HIV ribozyme were challenged with HIV. In both cases, we found that the ribozymes were effective only when expressed as capped, polyadenylated RNAs transcribed from Pol II cassettes that generate a cytoplasmically localized ribozyme that facilitates co-localization with its target. We also show that the inability of the other cassettes to support ribozyme-mediated inhibitory activity against their cytoplasmic target is very likely due to the resulting nuclear localization of these ribozymes. These studies demonstrate that the ribozyme expression cassette determines its intracellular localization and, hence, its corresponding functional activity.

Oligomerization and maturation of Na,K-ATPase: functional interaction of the cytoplasmic NH2 terminus of the beta subunit with the alpha subunit

Subunit assembly plays an essential role in the maturation of oligomeric proteins. In this study, we have characterized the main structural and functional consequences of the assembly of alpha and beta subunits of Na,K-ATPase. Xenopus oocytes injected with alpha and/or beta cRNA were treated with brefeldin A, which permitted the accumulation of individual subunits or alpha-beta complexes in the ER. Only alpha subunits that are associated with beta subunits become resistant to trypsin digestion and cellular degradation. Similarly, assembly with beta subunits is necessary and probably sufficient for the catalytic alpha subunit to acquire its main functional properties at the level of the ER, namely the ability to adopt different ligand-dependent conformations and to hydrolyze ATP in an Na(+)- and K(+)-dependent, ouabain-inhibitable fashion. Not only the alpha but also the beta subunit undergoes a structural change after assembly, which results in a global increase in its protease resistance. Furthermore, extensive and controlled proteolysis assays on wild-type and NH2-terminally modified beta subunits revealed a K(+)-dependent interaction of the cytoplasmic NH2 terminus of the beta subunit with the alpha subunit, which is likely to be involved in the modulation of the K(+)-activation of the Na,K-pump transport activity. Thus, we conclude that the ER assembly process not only establishes the basic structural interactions between individual subunits, which are required for the maturation of oligomeric proteins, but also distinct, functional interactions, which are involved in the regulation of functional properties of mature proteins.

The acute and long-term ocular effects of accelerated hypertension: a clinical and electrophysiological study

Thirty-four patients with accelerated hypertension were clinically examined. The visual evoked potential (VEP) and electroretinogram (ERG) were recorded: acutely in 12 patients, being repeated in 7 patients up to 6 months later. In the remaining 22 patients these tests were performed 2-4 years after presentation. Visual acuity was < or = 6/12 in 22 of 68 (32%) eyes at presentation and < or = 6/12 in 10 of 58 (19%) eyes at follow-up. The cause of severest loss of vision appeared to be anterior ischaemic optic neuropathy, found in 3 cases. During the acute stage 11 patients (92%) had abnormal VEPs and all had abnormal ERGs. The group mean P100 latency, of the 7 patients (14 eyes) seen acutely and followed up at 6 months, was 123.8 ms with significant recovery of latency (p < 0.005) to 110.9 ms. The ERGs, however, remained reduced and delayed. In those patients recorded 2-4 years after their acute episode the VEP was abnormal in only 2 patients (9%); group mean P100 latency was 109.1 ms. However, 18 patients (82%) had abnormal ERGs. We suggest that during the acute stage of accelerated hypertension there is a high incidence of ischaemic optic neuropathy that usually resolves but can cause a permanent anterior ischaemic optic neuropathy, in addition to vascular retinopathy that persists.

Aland island eye disease: clinical and electrophysiological studies of a Welsh family

Clinical and molecular genetic studies were performed on a single, large, white family, in which congenital nystagmus and moderate to high refractive error segregated as a sex linked trait with manifestation in some female carriers. In this family, affected males demonstrate myopia, but a high proportion of female carriers, and some of the possibly affected males, show hypermetropia. Clinical ophthalmic examination and electrodiagnostic studies of retinal function were fully compatible with a diagnosis of either incomplete congenital stationary night blindness or of Aland island eye disease. Previous studies have mapped both disorders to the proximal short arm of the X chromosome: our molecular studies support this localisation. Incomplete congenital stationary nightblindness and Aland Island eye disease could be considered as a single entity.

Polyadenylation of Na(+)-K(+)-ATPase beta 1-subunit during early development of Xenopus laevis

In fully grown Xenopus oocytes, the synthesis of beta-subunits is limiting for the formation of functional Na(+)-K(+)-adenosinetriphosphatase alpha/beta-complexes (Geering, K. FEBS Lett. 285: 189-193, 1991). In the present study, we show that during oocyte growth (from stage I to stage VI) alpha 1-, but not beta 1- or beta 3-isoform, mRNAs accumulate. In addition, beta-mRNAs are apparently sequestered in an untranslated pool in fully grown oocytes (stage VI). From fertilization to morulation, the total pools of alpha 1-, beta 1-, or beta 3-mRNAs vary little. Whereas polyadenylated [poly(A)+] alpha 1- and beta 3-isoform mRNAs did not change significantly, poly(A)+ beta 1-mRNA abundance increased three- to fourfold at morulation, accompanied by a parallel increase in beta 1-protein synthesis. After midblastula transition (i.e., at early gastrula) and during neurulation, poly(A)+ alpha 1- and beta 3-mRNAs accumulated rapidly, whereas poly(A)+ beta 1-mRNA accumulation was delayed by approximately 2 h, beginning only at early neurula. Our results indicate that 1) the abundance of poly(A)+ beta 1-mRNA is rate limiting during embryonic development for the assembly of alpha 1/beta 1-heterodimers, shown to be involved in the vectorial transport of sodium in kidney cells, and 2) the polyadenylation of beta 1-mRNA is a rate-limiting factor during morulation for the synthesis and assembly of new sodium pumps at the time of blastocoel fluid formation. The 3'-untranslated region of beta 1-mRNA (but not of alpha 1-mRNA) expresses cytoplasmic polyadenylation elements (CPEs) with the consensus sequence AXX-AUUUU(A/U)(A/U)(A/U). A role of CPE in the differential polyadenylation of alpha 1- and beta 1-mRNA is proposed.

Genetic mapping of a cone and rod dysfunction (Aland Island eye disease) to the proximal short arm of the human X chromosome

A five generation family with an X linked ocular disorder has been investigated. The major clinical features were reduced visual acuity, nystagmus, and myopia. Although impaired night vision was not a symptom, using psychophysical and electrophysiological testing both rod and cone function were found to be abnormal in all affected males. No abnormality was detected in carrier females. Gene location studies showed X linked transmission of a gene that maps to proximal Xp11. The findings observed in this cohort are similar to those previously reported in both congenital stationary night blindness type 2 (CSNB2) and Aland Island eye disease (AIED). This study addresses whether CSNB2 and AIED are a single entity or whether the latter is a subset of the former.

Pigment epitheliopathy with serous detachment of the retina following intravenous iron dextran

We report a case of pigment epitheliopathy with serious detachment of the retina in a 23-year-old man following a total dose infusion of iron dextran. Initial impairment of visual acuity resolved spontaneously, along with changes in the electro-oculogram and fundus fluorescein angiogram. Ocular features of systemic iron toxicity are reviewed and the pathophysiology discussed. Practitioners using total dose iron infusion should be aware of the possible ocular complications.

Regulation of alpha 1-beta 3-NA(+)-K(+)-ATPase isozyme during meiotic maturation of Xenopus laevis oocytes

During progesterone-induced maturation of Xenopus oocytes, the transport and ouabain binding capacity of Na(+)-K(+)-ATPase at the plasma membrane is completely downregulated. To elucidate the mechanism and the physiological significance of this process, we have followed the fate of oocyte alpha-beta 3-Na(+)-K(+)-ATPase complexes during meiotic maturation and early embryonic development. An immunocytochemical follow-up of the catalytic alpha-subunit, ouabain binding studies, cell surface iodination, and oocyte cell fractionation combined with immunochemical subunit detection provides evidence that following progesterone treatment Na(+)-K(+)-ATPase molecules are retrieved from the oocyte plasma membrane. The enzyme complexes are recovered in an active form in an intracellular compartment in both in vitro and in vivo matured eggs. Exogenous Xenopus alpha 1- and beta 1-complexes expressed in the oocyte from injected cRNAs are regulated by progesterone similar to endogenous Na(+)-K(+)-ATPase complexes. Finally, active Na(+)-K+ pumps internalized during oocyte maturation appear to be redistributed to plasma membrane fractions during blastula formation in Xenopus embryos. In conclusion, our data suggest that endocytosis of alpha 1- and beta 3-complexes during meiotic maturation of Xenopus oocytes is responsible for downregulation of Na(+)-K(+)-ATPase activity and results in an intracellular pool of functional enzymes, which might be reexpressed during early development in response to physiological needs.

Mesoderm induction in Xenopus laevis distinguishes between the various TGF-beta isoforms

Induction of mesoderm in ectodermal explants of Xenopus laevis blastula embryos had previously been shown to respond selectively to TGF-beta 2, with TGF-beta s 1 and 5 having no activity in this assay. As TGF-beta s 1, 2, and 3 are frequently coexpressed in tissues, we wished to examine the activity of TGF-beta 3 relative to that of TGF-beta s 1 and 2 in this assay as well as in other in vitro assays. We report here that when the activity of recombinant TGF-beta 3 is normalized to that of TGF-beta 1 in the assay for growth inhibition in CCL-64 cells, it is also equal to that of TGF-beta 1 in assays for stimulation of both anchorage-independent growth of rat NRK cells and chemotaxis of human monocytes. In contrast, in the assay for mesoderm induction, recombinant TGF-beta 3 is 10-fold more active than TGF-beta 2, inducing expression of muscle specific alpha-actin at concentrations as low as 1 ng/ml. These results suggest that more complex systems, in contrast to individual cell types, may respond selectively to the various TGF-beta isoforms and that there might be biological consequences of TGF-beta isoform switching in vivo.

Methadone maintenance program for AIDS-affected opiate addicts

To slow the spread of AIDS, it may be important for substance abuse treatment programs to give priority admission to patients who are HIV-infected and infectious. A new program is described that provides methadone maintenance treatment to opiate addicts who are "AIDS affected"--heroin addicts diagnosed with AIDS, AIDS-related complex (ARC), or other significant symptoms of HIV infection. The program aims to protect the health of patients and to protect the general public by slowing the spread of the human immunodeficiency virus (HIV). This article describes the program's history and goals, its referral and patient admission process, methods of assessment and treatment planning, medical care, counseling procedures, tolerance for misbehavior, philosophy toward eventual detoxification, and procedures that maintain confidentiality.

Proximal chronic inflammatory polyneuropathy with multifocal conduction block

The pathological findings in proximal and distal nerve biopsy specimens are described in a patient with the clinical and electrophysiological features of chronic inflammatory polyneuropathy with multifocal conduction block. Proximal onion bulb hypertrophic changes in the brachial plexus were associated with inflammatory cell infiltrates. In contrast, the sural nerve biopsy specimen showed a mild picture of mixed axonal degeneration and demyelination-remyelination without inflammatory infiltration.

Electrophysiology and metallosis: support for an oxidative (free radical) mechanism in the human eye

Nine cases of metal intraocular foreign body are presented. This study investigates the use of electrodiagnostic techniques in the diagnosis of metallosis and as a prognostic indicator. The electro-oculogram (EOG) and the electoretinogram (ERG) indicate that there are two mechanisms of metallosis, one of which involves cytotoxic damage by siderosomes, and the other lipid peroxidation of photoreceptor outer segments and retinal pigment epithelium. The evidence suggests that the location of the foreign body in the eye determines whether either or both of these mechanisms occur. We propose that these tests can help the ophthalmologist decide when a foreign body has to be removed and give information as to the mechanism of the pathological process.

Cost-effective selection of fire fighter recruits

To discriminate suitable fire fighters from recurring large groups of applicants, an objective test battery was developed which screened applicants on the basis of physical, psychomotor, and mental abilities. The physical and psychomotor selection procedures first involved fundamental tests of general aerobic endurance, upper body strength, and anaerobic endurance. Successful candidates progressed to more specific tests. Measurements were made of height, weight, hamstring flexibility, balance, strength, upper body flexibility, hand-eye coordination, and the ability to negotiate a fire fighting simulation course. Results of these tests were weighted, allocating 25% to physical tests, 20% to psychomotor tests, and 39% to the simulation course. These scores were then combined with scores of several knowledge tests weighted to be 16% of the whole. This provided a computer-generated ability profile of the top applicants which was considered at their interview before a final selection board of fire service officers. Selected candidates were then required to pass a medical examination. Pearson correlation coefficient analysis of 1984 test results demonstrated general independence of the tests (R = -0.34 to R = 0.52), with the exception of bilateral grip strength (R = 0.77). The first four trials of the selection procedure screened 3,172 applicants, 16.4% of whom were finally selected for interview. City officials estimated that based on a comparison of new and previously used selection procedures, cost savings of +92,500 were being achieved by 1984.

Painful lumbosacral plexopathy with elevated erythrocyte sedimentation rate: a treatable inflammatory syndrome

Six patients had a syndrome of painful lumbosacral plexopathy and elevated erythrocyte sedimentation rate. Sural nerve biopsy in each case showed axonal degeneration and epineurial arterioles surrounded by mononuclear inflammatory cells. Differential fascicular involvement suggested an ischemic cause in three nerves, but no patient had a necrotizing vasculitis. None of the six patients had vasculitis or cancer. Three of the six were diabetic and were initially thought to have diabetic plexopathy, but deterioration continued despite control of the diabetes. These six patients appeared to have an ischemic neuropathy with an immunological basis. Five were treated with immunosuppressant drugs, and in four the plexopathy improved or was arrested. The pathogenesis is unclear, but postmortem findings in one case suggest that the syndrome does not stem from an underlying vasculitis.

Morphometric and biochemical studies of peripheral nerves in amyotrophic lateral sclerosis

Phrenic nerves of 11 patients with amyotrophic lateral sclerosis studied postmortem contained only 33% of the normal number of large myelinated fibers (9 controls; p less than 0.001). In the phrenic nerves of these patients, there were 18% fewer large myelinated fibers in the distal segment than in the proximal segment (p less than 0.025). The ratio of axonal circumference to myelin lamellae in large myelinated fibers in the distal segment was 34% greater than that in control fibers (p less than 0.002). The proportion of acute axonal degeneration was the same at all levels (48.0 +/- 13.7%). Sural nerves of 21 patients with amyotrophic lateral sclerosis had more acute axonal degeneration and 30% fewer myelinated fibers (p less than 0.05) than controls; evidence of degeneration also extended to unmyelinated fibers. The amount of axonal transport of acetylcholinesterase in 9 sural nerves determined in vitro was reduced by 24% (p less than 0.05) and the apparent transport rate was reduced by 44% (p less than 0.01) compared with 4 controls. These findings show that in amyotrophic lateral sclerosis a small degree of dying-back change and of distal axonal atrophy is superimposed on the degeneration of motor neuron cell bodies, and that the disease effects spread beyond the motor neurons.

Sympathetic postganglionic unmyelinated axons in the rat peripheral nervous system

We determined the contribution made to the unmyelinated axon population of the rat peripheral nervous system by sympathetic paravertebral ganglion cells. Sympathectomy, achieved by administration of guanethidine to neonatal rats, led to atrophy of the sympathetic paravertebral ganglion chain, a 95% decrease in peripheral nerve norepinephrine, and loss of 20 to 26% of the unmyelinated axons in a cutaneous nerve (sural), a muscular nerve (nerve to soleus), and a mixed nerve (sciatic). These data indicate that up to a quarter of the total population of peripheral nerve unmyelinated axons are sympathetic ganglia-derived.

Unmyelinated axon subpopulations in the rat peripheral nervous system

Using the neurotoxin capsaicin, we examined subpopulations of unmyelinated axons in mixed (sciatic), cutaneous (sural), and muscular (nerve to soleus) nerves. Administration of capsaicin to neonatal rats caused reduction of the sciatic nerve immunoreactive (IR)-substance P (by 45%) and IR-somatostatin (by 84%) contents. This correlated with a substantial reduction in unmyelinated axons in the sciatic and sural nerves (45% and 65%, respectively), although there was no significant decrease in unmyelinated axons in the nerve to soleus. In a parallel study, we have shown that sympathetic ganglia-derived unmyelinated axons account for about 20 to 25% of the total unmyelinated axon population in both the sural nerve and the nerve to soleus. Thus, in the sural nerve, the majority of unmyelinated axons are dorsal root ganglia-derived, contain either substance P or somatostatin, and are capsaicin-sensitive; whereas in the nerve to soleus, the majority of unmyelinated axons are dorsal root ganglia-derived but are insensitive to capsaicin and do not contain substance P or somatostatin. These latter unmyelinated axons presumably contain a yet to be defined neurotransmitter and may be the axons connecting with muscular ergoreceptors, a subpopulation of unmyelinated axons that are biochemically and functionally distinct from the unmyelinated axons of cutaneous nerves.