The functional neuroanatomy of social behaviour: changes in cerebral blood flow when people with autistic disorder process facial expressions

Although high-functioning individuals with autistic disorder (i.e. autism and Asperger syndrome) are of normal intelligence, they have life-long abnormalities in social communication and emotional behaviour. However, the biological basis of social difficulties in autism is poorly understood. Facial expressions help shape behaviour, and we investigated if high-functioning people with autistic disorder show neurobiological differences from controls when processing emotional facial expressions. We used functional MRI to investigate brain activity in nine adults with autistic disorder (mean age +/- standard deviation 37 +/- 7 years; IQ 102 +/- 15) and nine controls (27 +/- 7 years; IQ 116 +/- 10) when explicitly (consciously) and implicitly (unconsciously) processing emotional facial expressions. Subjects with autistic disorder differed significantly from controls in the activity of cerebellar, mesolimbic and temporal lobe cortical regions of the brain when processing facial expressions. Notably, they did not activate a cortical 'face area' when explicitly appraising expressions, or the left amygdala region and left cerebellum when implicitly processing emotional facial expressions. High-functioning people with autistic disorder have biological differences from controls when consciously and unconsciously processing facial emotions, and these differences are most likely to be neurodevelopmental in origin. This may account for some of the abnormalities in social behaviour associated with autism.

Coding changes in the poliovirus protease 2A compensate for 5'NCR domain V disruptions in a cell-specific manner

Polioviruses are single-stranded RNA viruses with an unusually long noncoding region (NCR) at the 5' end predicted to have an elaborate secondary structure made up of six domains. Mutations in domain V of the poliovirus 5'NCR that disrupt secondary structure are responsible for attenuation of the virus and a temperature-sensitive (ts) phenotype in vitro. In addition to direct back mutation or compensatory second site mutation in the 5'NCR as previously documented, the ts phenotype was found to be compensated for in monkey kidney cells in vitro by a coding change in the protease 2A. These coding changes were found throughout the protease with no obvious pattern or trend. They were not all found to be equivalent and limited in ability to compensate for the severest domain V disruption. The compensatory effect of the 2A changes was found to be cell specific, having no effect on monkey neurovirulence and in a mouse cell line but a significant effect in two monkey cell lines and a human epithelial line.

Percutaneous gastrojejunostomy in amyotrophic lateral sclerosis

We have performed a retrospective review of the use of a percutaneous gastrojejunostomy in patients with amyotrophic lateral sclerosis (ALS). Forty-one patients with initial bulbar manifestations of ALS and 32 patients with initial limb manifestations underwent a percutaneous gastrojejunostomy under fluoroscopic control using the Rankin gastrojejunostomy tube. Survival characteristics were compared with 86 bulbar onsetting and 207 limb onsetting ALS patients who did not require nutritional support. The 30-day mortality rate was 9.6% (respiratory death in three bulbar onsetting patients and four limb onsetting patients) and the 30 day morbidity rate was 4.1% (one operative site infection and intraperitoneal leakage in two patients). The most frequent long-term complication was the requirement for tube changing (blockage in six; dislodgment in two). Gastric reflux was not described amongst the treated patients. Overall survivorship (symptom onset to death) was less in the bulbar onsetting patients receiving a gastrojejunostomy tube than in the control population (median survival 22.0 vs. 33.7 months, respectively, P=0.005). As a group, the median survivorship for limb onsetting patients was not different for those receiving a gastrojejunostomy than for those who did not. However, a significant reduction in survival was observed in limb onsetting patients receiving a gastrojejunostomy early in the course of their disease (P=0.001) compared to those with a longer duration prior to the procedure. This was not observed in the bulbar onsetting patients. In both patient populations, no relationship was observed between survival post-gastrojejunostomy and the severity of pulmonary involvement at the time of the intervention, serum chloride, or age at onset. These studies demonstrate that a percutaneous gastrojejunostomy is a well-tolerated and safe alternative technique for enteral nutritional support in ALS patients. It also offers the advantage of not requiring either a general anaesthetic at the time of the procedure or instrumentation through the oropharynx. We have also observed that limb onsetting patients requiring a gastrojejunostomy early in the course of their illness are in a distinctive, less favorable, prognostic group.

Spatial working memory in Asperger's syndrome and in patients with focal frontal and temporal lobe lesions

Spatial working memory (SWM) was investigated in 15 patients with Asperger's syndrome (AS) comparing their performance to 18 age- and IQ-matched control subjects. An additional comparison was made with 20 unilateral frontal excision patients [9 right (RFL); 11 left (LFL)] and with 38 unilateral temporal lobectomy patients [18 right (RTL); 18 left (LTL)], the frontal and temporal lobe patients having separate matched control groups. SWM was tested using the Executive Golf Task, a test that also measures spatial strategy formation. The AS group showed a substantial deficit on SWM, but no impairment in strategy formation. The LFL showed the same pattern of impairment, but with a less substantial deficit. The RFL group showed a large deficit, but some of this was accounted for by a strategy formation impairment. Of the temporal lobe lesions groups, only the RTL group was impaired on SWM, but this group showed normal strategy formation. It was concluded that the SWM deficit in AS may reflect a more general difficulty in accessing different types of representations in order to guide voluntary behavior, providing at least a partial explanation for the executive deficits found in AS.

Sequential changes in trace metal, metallothionein and calmodulin concentrations in healing skin wounds

Metalloenzymes have an important role in repair and regenerative processes in skin wounds. Demands for different enzymes vary according to the phase in the healing cascade and constituent events. Sequential changes in the concentrations of calcium, copper, magnesium and zinc were studied in the incisional wound model in the rat over a 10 d period. Copper levels remained low (< 10 microg/g dry weight) throughout, but calcium, magnesium and zinc increased from wounding and peaked at about 5 d at a time of high inflammation, granulation tissue formation and epidermal cell proliferation. Metal concentrations declined to normal by 7 d when inflammation had regressed, re-epithelialisation of the wound site was complete and the 'normalisation' phase had commenced. Although the wound was overtly healed by 10 d, the epidermis was still moderately hyperplastic. In view of competitive binding of trace metals at membrane receptors and carrier proteins, the ratios or balance between these trace metals was examined and the significance is discussed. Using immunocytochemistry, we demonstrated increases in metallothionein immunoreactivity as an indication of zinc and copper activity in the papillary dermis and in basal epidermal cells near the wound margin 1-5 d after wounding. This is consistent with metalloenzyme requirements in inflammation and fibrogenesis. Calmodulin, a major cytosolic calcium binding protein was highest in maturing keratinocytes and in sebaceous gland cells of normal skin; it was notably more abundant in the epidermis near the wound margin and in re-epithelialising areas at a time when local calcium levels were highest.

Effects of a 2-hour cheerleading practice on dynamic postural stability, knee laxity, and hamstring extensibility

STUDY DESIGN

One group; pretest, posttest design.

OBJECTIVE

To assess the effect of a 2-hour cheerleading practice on the anterior knee laxity, hamstring extensibility, and dynamic postural stability (preferred stance leg during vision-denied unilateral stance) of 17 nonimpaired members of a college cheerleading team (8 females, 9 males; 18-25 years old).

BACKGROUND

Anterior knee laxity and hamstring extensibility increase following exercise. The relationship between exercise induced anterior knee laxity, hamstring extensibility, and dynamic postural stability, however, has not been examined.

METHODS AND MEASURES

Pre- and postpractice measurements were compared using paired t tests and Bonferroni's correction for multiple comparisons. A 3 x 2 analysis of variance (force level applied to the arthrometer by condition) and Tukey honest significant difference post hoc test were used to evaluate specific arthrometer force level by condition effects (P < .05).

RESULTS

Mean laxity at 133 N and hamstring extensibility increased (mean +/- SD) 1.5 +/- 1 mm and 3 +/- 4 degrees, respectively, following practice. Mean medial-lateral stabiliometer platform angulation (frontal plane position) moved medially following practice (2.9 +/- 3 degrees) and produced a weak correlation with increased knee laxity (r = 0.58). Hamstring extensibility did not significantly relate to stabiliometry or knee laxity variables.

CONCLUSIONS

The relationship between the medially directed platform angulation and the increase in anterior knee laxity following cheerleading practice suggests a relationship between subtalar joint position and anterior cruciate ligament strain.

Itchy folliculitis and human immunodeficiency virus infection: clinicopathological and immunological features, pathogenesis and treatment

The predominant itchy folliculitis associated with human immunodeficiency virus (HIV) infection appears to be an eosinophilic folliculitis (EF). This is characterized by lytic degeneration of sebaceous glands and an inflammatory infiltrate in which eosinophils and CD8+ T lymphocytes predominate. All patients have low CD4 counts and present late on in their HIV disease. Lesional distribution is mainly truncal, with a significant proportion also having facial involvement. Our prospective survey has shown that it is impossible to differentiate clinically between infective folliculitis and EF, and we recommend therefore that all cases are biopsied. We review the clinicopathological and immunological aspects of HIV-associated itchy folliculitis, in particular HIV-associated EF as well as current theories on pathogenesis and treatment. We suggest that HIV-associated EF is an autoimmune disease with the sebocyte or some constituent of sebum acting as the autoantigen.

Cytoadherence, pathogenesis and the infected red cell surface in Plasmodium falciparum

The particular virulence of Plasmodium falciparum compared with the other malaria species which naturally infect humans is thought to be due to the way in which the parasite modifies the surface of the infected red cell. Approximately 16 hours into the asexual cycle, parasite encoded proteins appear on the red cell surface which mediate adherence to a variety of host tissues. Binding of infected red cells to vascular endothelium, a process which occurs in all infections, is thought to be an important factor in the pathogenesis of severe disease where concentration of organisms in particular organs such as the brain occurs. Binding to uninfected red cells to form erythrocyte rosettes, a property of some isolates, is linked to disease severity. Here we summarise the data on the molecular basis of these interactions on both the host and parasite surfaces and review the evidence for the involvement of particular receptors in specific disease syndromes. Finally we discuss the relevance of these data to the development of new treatments for malaria.

Depletion of cutaneous peptidergic innervation in HIV-associated xerosis

Severe xerosis occurs in approximately 20% of human immunodeficiency virus seropositive patients. Changes in cutaneous innervation have been found in various inflammatory skin diseases and in xerotic skin in familial amyloid. We have therefore carried out a quantitative examination of the cutaneous peptidergic innervation in human immunodeficiency virus-associated xerosis. Immunohistochemistry and image analysis quantitation were used to compare total cutaneous innervation (protein gene product 9.5), calcitonin gene-related peptide, substance P, and vasoactive intestinal peptide peptidergic fibers, at two sites in the skin of human immunodeficiency virus-associated xerosis patients (upper arm, n = 12; upper leg, n = 11) and site-matched seronegative controls (upper arm, n = 10; upper leg, n = 10). Measurement of lengths of fibers of each type was carried out for each subject in the epidermis and papillary dermis, and around the sweat glands. Immunostained mast cells in these areas were counted. Epidermal integrity and maturation were assessed by immunostaining for involucrin. There were significant (Mann-Whitney U test; p < 0.02) decreases in total lengths of protein gene product 9.5 fibers in both epidermis/papillary dermis and sweat gland fields; of calcitonin gene-related peptide innervation in the epidermis/papillary dermis; and of substance P innervation of the sweat glands. There were no differences in the distribution of mast cells, or in the epidermal expression of involucrin. Depletion of the calcitonin gene-related peptide innervation may affect the nutrient blood supply of the upper dermis, and the integrity and function of basal epidermis and Langerhans cells. Diminished substance P innervation of the sweat glands may affect their secretory activity. Both of these changes may be implicated in the development of xerosis.

3D coronary artery imaging with phase reordering for improved scan efficiency

Three-dimensional (3D) coronary imaging has the potential to overcome problems resulting from vessel tortuosity and to reduce partial volume effects. With these techniques, however, acquisition times are long and respiratory motion artifacts problematical. This work describes the development of a method that applies phase encode reordering to 3D acquisitions, allowing larger navigator acceptance windows to be used, with a consequent reduction in acquisition time. This method is compared with navigator acceptance window methods (the acceptance-rejection algorithm and the diminishing variance algorithm) and the retrospective respiratory gating technique, both in vitro and in vivo. The use of phase reordering with a 10 mm acceptance window provided a significant increase in scan efficiency over a non-reordered 5 mm method (P<0.001) with no significant change in image quality, and a significant increase in image quality compared with a non-reordered image acquired in the same time (P<0.05). A significant improvement in both image quality and scan efficiency was demonstrated over the retrospective respiratory gating method (P<0.05).

Spectre at the feast

The government's vision, reflected in both the white paper The New NHS: Modern, Dependable (Department of Health, 1997) and circulars since is of GPs and community nurses working together in primary care groups to shape services for patients. But the short history of PCGs has seen nurses having to fight for representation. There is also cynicism about the outcome, nurses having a maximum of two members, GPs seven. Is an equal working relationship really possible? This snapshot survey examines professionalism and collaborative working in primary care. The results suggest that without changes in structure, understanding and attitudes by both doctors and nurses a relationship of equality is not likely.

Interleukin-4 and the interleukin-4 receptor in allergic contact dermatitis

Cutaneous immune responses involving T helper (TH) type 1 (TH1) and type 2 (TH2) T cells, characterised by secretion of interferon-gamma (Ifn-gamma) and interleukin-4 (IL-4), respectively, have both been reported in allergic contact dermatitis (ACD). We used immunohistochemistry to localize expression of IL-4 in ACD lesions and unaffected skin. Atopic dermatitis (AD) and psoriasis biopsies provided positive and negative IL-4 immunoreactivity controls. To investigate the role of IL-4 in ACD, we investigated expression of IL-4 receptors in ACD, AD and psoriatic skin. IL-4 immunoreactivity was found in cells in the dermal infiltrate in 3 out of 7 ACD lesions, but not in unaffected skin from these patients. IL-4 immunoreactivity was found in the dermal infiltrate of all lesional and unaffected AD biopsies, but in none of the psoriatic biopsies. IL-4 receptor alpha chain immunoreactivity, associated with dermal mast cells, was found in all patients. Local expression of IL-4 in ACD indicates either TH2 or TH0 immunoregulation in some allergic contact dermatitis lesions. Our findings do not support exclusive TH1 or TH2 cutaneous immune responses in ACD. Expression of IL-4 receptors by cutaneous mast cells provides a route through which local effects of IL-4 might be mediated.

[Cholesterol in beef, pork, chicken and their products commercialized in Maringá, Paraná, Brazil]

A rapid method developed by Al-Hasani et al. with modifications for cholesterol determination was applied in samples of beef, pork, chicken and meat products. Analyses of cholesterol were performed by capillary gas chromatography. The obtained results showed that chicken presented higher concentration (126.96 to 188.29 mg/100 g) of cholesterol in comparison to beef and pork and similar to meat products, except bovine liver that presented 265.03 mg/100 g. Cholesterol values of beef and pork samples were considered low due to the absence of superficial fat in meat samples.

Endoscopic management of pancreatic pseudocysts

Pancreatic pseudocyst is a major complication of acute and chronic pancreatitis. Surgical drainage, the mainstay of therapy for this condition, is associated with 5% mortality, 25% morbidity, and 10% recurrence rates. Efforts to improve these figures and reduce the typically long hospitalizations have brought about percutaneous and endoscopic drainages. This article describes the endoscopic techniques and attempts to summarize their results based on a literature review. Before endoscopic drainage is carried out, other cystic lesions must be excluded with clinical history, computed tomography findings, and perhaps cyst fluid CEA content and cytology. Endoscopic techniques include wide transmural incision, transmural puncture and stenting, and transpapillary stenting. Either transgastric or transduodenal drainages can be carried out depending on the proximity of the pseudocyst to the gastrointestinal lumen. Endosonography has become an integral part of the transmural procedure because it can help diagnose cystic neoplasms, localize pseudocysts, detect submucosal vessels, and measure the cyst to mucosal distance for transmural punctures. Temporary nasocystic drains are often used to complement stenting during the initial treatment phase. Overall, the endoscopic experience in expert hands is associated with 94% initial technical success, 90% cyst resolution, and 16% recurrence rates. Additional nonendoscopic interventions, mostly surgical, are necessary in 17% of patients. Complication rate is 20%, with < 1% mortality. These data suggest that endoscopic drainage should become an accepted modality in the treatment of pseudocysts. Because of significant technical difficulty and potential risks, endoscopic drainages should only be carried out by experienced endoscopists and at well-equipped facilities.

Retinoid X receptors

Retinoids are metabolites of retinol (vitamin A), which act as signalling molecules in embryogenesis and as stimulators of cellular differentiation. The potency of retinoids as differentiating agents has led to their successful use in treating skin diseases and some forms of cancer. The retinoid X receptors (RXRs) are receptors for the vitamin A metabolite 9-cis retinoic acid, and they are members of the steroid/thyroid hormone receptor superfamily of DNA binding nuclear hormone receptor. The RXRs are also cofactors required for transcription activated by some other members of the steroid/thyroid hormone receptor superfamily, including the all-trans retinoic acid, thyroid hormone, vitamin D and peroxisome proliferator-activated receptors. The biological importance of the RXRs has been demonstrated in recent genetic studies which have shown that some RXR null mutations in mice have phenotypic effects similar to vitamin A deficiency.

Constitutive endothelial and inducible nitric oxide synthase in inflammatory dermatoses

We have used immunohistochemistry to localize the expression of the constitutive endothelial and inducible forms of the enzyme nitric oxide synthase (NOS) in skin from involved and uninvolved sites in patients with atopic dermatitis (AD) and allergic contact dermatitis (CD). Endothelial NOS (eNOS) immunoreactivity was localized to vascular endothelium in the dermis of both involved and uninvolved skin from all patients. Inducible NOS (iNOS) immunoreactivity was found to be closely associated with the upper dermal microvasculature in all the involved AD biopsies, but only in two of 10 uninvolved AD biopsies. CD biopsies were taken from 10 positive skin patch test sites and iNOS immunoreactivity was detected in all of these. iNOS immunoreactivity was detected in only one of the negative patch test biopsies. Both the extent and intensity of iNOS immunoreactivity was lower in CD than in AD skin lesions. The presence of eNOS in the skin is necessary for constitutive NO-mediated dilatation of the dermal vasculature. Induction of iNOS in the dermal endothelium and in perivascular inflammatory cells may be significant with respect to the roles of NO in both the vasodilatory component of the inflammatory response and in the modulation of immune responses in the skin.

Investigations into the molecular size and shape of tomato extensin

The molecular characteristics of soluble extensin from tomato have been investigated. An apparent molecular mass greater than 240 kDa has been previously observed with the shape-dependent method of gel-filtration chromatography [Brownleader and Dey (1993) Planta (Berlin) 191, 457-469]. Tomato extensin is a heavily glycosylated protein that does not migrate into SDS/polyacrylamide gels. This shape-dependent behaviour raises doubts about agreement between the observed apparent mass and the absolute value. The molecular mass measured with matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) was 72.3 kDa, with no evidence of any other species except a doubly charged ion. The sample was therefore considered to be monodisperse under the conditions used. Electron microscopy of soluble extensin showed the presence of particles 40-50 nm in length and 2.0-2.5 nm in width. A minority of these particles showed a central 'kink'. A number of smaller and generally wider particles (20 nm x 2-4 nm) were considered to be folded monomers and larger particles were thought to be dimers. Sedimentation analysis showed that extensin exists in a rapid monomer-dimer equilibrium in the concentration range and buffer used. Sedimentation equilibrium data gave a Kd of 8.5 microM and sedimentation velocity data generated a Kd between 1 and 10 microM. The concentration dependence of the measured sedimentation coefficient was used, together with hydrodynamic bead modelling, to define plausible shapes for monomer and dimer. This suggests that monomeric extensin is an elongated rod of length 40 nm and width 2 nm, which forms staggered dimers of average length 50 nm and width 3 nm. Extensin is an integral component of the primary cell wall. The physical characteristics (size, shape and form) of the rod-like extensin have been evaluated in this paper so that the role that extensin plays in primary cell wall architecture and during plant disease resistance can be more fully understood.

Role of mutations G-480 and C-6203 in the attenuation phenotype of Sabin type 1 poliovirus

Of the 55 point mutations which distinguish the type 1 poliovirus vaccine strain (Sabin 1) from its neurovirulent progenitor (P1/Mahoney), two have been strongly implicated by previous studies as determinants of the attenuation phenotype. A change of an A to a G at position 480, located within the 5' noncoding region, has been suggested to be the major attenuating mutation, analogous to the mutations at positions 481 and 472 in poliovirus types 2 and 3, respectively. In addition, the change of a U to a C at position 6203, resulting in an amino acid change in the polymerase protein 3D, has also been implicated as a determinant of attenuation, albeit to a lesser extent. To assess the contributions of these mutations to attenuation and temperature sensitivity, reciprocal changes were generated at these positions in infectious cDNA clones of Sabin 1 and P1/Mahoney. Assays in tissue culture and primates indicated that the two mutations make some contribution to the temperature sensitivity of the Sabin 1 strain but that neither is a strong determinant of attenuation.

Expression of the chicken retinoid X receptor-gamma gene in migrating cranial neural crest cells

We have used in situ hybridisation to whole chick embryos with digoxygenin-labelled probes to investigate the distribution of RXR-gamma transcripts during neural crest cell migration in the developing head and the anterior of the trunk (the vagal region), where neural crest cells make a substantial contribution. We have found that RXR-gamma transcripts are a good marker for migrating neural crest cells in the chick embryo. RXR-gamma transcripts were first detected in cells that had recently emerged from the neural crest, providing an earlier marker for neural crest cells than the HNK-1 epitope. The pattern of RXR-gamma transcript distribution is dynamic in the developing chick head, and changes in a pattern which is coincident with the migration of cells containing RXR-gamma transcripts and the gradual restriction of RXR-gamma transcripts to specific differentiating neural crest derivatives. Transcripts appeared to be present initially in migrating neural crest cells thoughout the developing head, but gradually became restricted to some crest-derived populations and absent from others. By stage 15, RXR-gamma transcripts were not detectable in neural-crest-derived ectomesenchymal cells, although they were still found in cells contributing to the cranial ganglia and their roots.

Plasmodium falciparum rosetting is associated with malaria severity in Kenya

Rosette formation in 154 fresh Plasmodium falciparum isolates from Kenyan children with mild (n = 54), moderate (n = 64), or severe (n = 36) malaria was studied to determine whether the ability to form rosettes in vitro is correlated with malaria severity. There was a wide distribution of rosette frequencies within each clinical category; however, a clear trend towards higher rosette frequency with increasing severity of disease was seen, with the median rosette frequency of the mild-malaria group (1%; range, 0 to 82%) being significantly lower than those of the moderate-malaria group (5%; range, 0 to 45%; Mann-Whitney U test, P < 0.02) and the severe-malaria group (7%; range, 0 to 97%; Mann-Whitney U test, P < 0.003). Within the severe-malaria category there was no difference in rosetting among isolates from cerebral malaria patients or those with other forms of severe malaria. We also examined the ABO blood groups of the patients from whom isolates were obtained and found that isolates from group O patients (median rosette frequency, 2%; range 0 to 45%) rosetted less well than those from group A (median, 7%; range 0 to 82%; Mann-Whitney U test, P < 0.01) or group AB (median, 11%; range 0 to 94%; Mann-Whitney U test, P < 0.03). We therefore confirm that rosetting is associated with severe malaria and provide further evidence that rosetting is influenced by ABO blood group type. Whether rosetting itself plays a direct role in the pathogenesis of severe malaria or is a marker for some other causal factor remains unknown.

Diversity management: practical application in a health care organization

Lee Gardenswartz and Anita Rowe extend our lead author's contributions to diversity management by suggesting a framework for organizational development that can create an "inclusive" environment for enhancing the productivity and service quality of its staff. The framework includes attention to (1) individual attitudes and beliefs, (2) organizational values and policies, and (3) management skills and practices. The common ground among these three aspects is change. Gardenswartz and Rowe posit that substantial change is necessary to realize maximum value from diversity, and therefore barriers to organizational, attitudinal and managerial behavioral change must be acknowledged and overcome.

Plasmodium falciparum: a family of sulphated glycoconjugates disrupts erythrocyte rosettes

The ability of Plasmodium falciparum-infected erythrocytes to form spontaneous rosettes with uninfected red cells is a parasite adhesion property which has been associated with severe malaria. The mechanism of rosetting remains unknown, but the ability of heparin to disrupt rosettes has been recognised previously. In this paper we show that a group of sulphated glycoconjugates including sulphatide, dextran sulphate, and fucoidan are more effective rosette reversing agents than heparin and are active against both laboratory strains and wild isolates. Other related anionic glycosaminoglycans such as the chondroitin sulphates A, B, and C and hyaluronic acid have no effect on rosette formation. This family of sulphated glycoconjugates which are active against rosettes is also known to inhibit sporozoite invasion of hepatocytes and merozoite reinvasion of erythrocytes, suggesting that sulphated glycoconjugate interaction may be an important process in cell adhesion at different stages in the plasmodial life cycle.

Effect of parathyroid hormone-related peptide supplementation of soy protein formulas in the neonatal pig model

PTH-related peptide (PTHrP) is found in all milks, including human and pig. To define a role for PTHrP in milk, 2-day-old piglets were randomized to receive soy formula devoid of PTHrP or supplemented with 1 nM synthetic PTHrP(1-86) (n = 8 per group). The number of serum samples with detectable PTHrP by immunoassay (Incstar) and radiometric assay (Nichols) was 9 of 33 and 3 of 13 in PTHrP- and 8 of 27 and 3 of 15 in PTHrP+ formula-fed piglets and 8 of 14 and 7 of 12 in naturally suckling piglets, respectively. Serum and urine concentrations of calcium and magnesium and total and bone alkaline phosphatase were similar in both groups at 3, 6, 10, and 17 days of age. No differences were seen in bone mineral content of the tibia measured by single-photon absorptiometry (BMC 0.22 +/- 0.06 and 0.22 +/- 0.10) or dual x-ray absorption (BMC 1.43 +/- 0.36 and 1.31 +/- 0.78) either in vivo or on excised bone or by measurement of Ca, Mg, or P content or total bone ash (1.26 +/- 0.26 and 1.38 +/- 0.28 mg). Intestinal histology, serum intestinal alkaline phosphatase, and net absorption and retention of Ca, Mg, and P in balances from age 11-17 days were all similar. As in humans, however, a developmental pattern was seen for phosphorus regulation in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular mechanisms of sequestration in malaria

Cell surface molecules have received intense attention in recent years because of the central roles they play at the interface between the external environment and the cellular interior. Their functions include adhesion to other cells or extracellular matrices, protection against hostile physical, chemical and biological agents and the transport of metabolites into and out of the cell. In addition, cell surface molecules transduce signals across the cell membrane, relaying information inwards and presenting altered characteristics to the exterior as the environment changes.

Recognizing the power of diversity

"The trouble with the future is that it usually arrives before we are ready for it." While Arnold H. Glasgow did not have diversity in mind when he made this statement, his thought is relevant to that topic nevertheless. In fact, almost everything in the health care environment of the 1990s is fluid, making the future a question mark. Among these changes is the demographic composition of students entering medical school and of patients. Consider the following. While 14 percent of today's physicians are people of color, that number increases to 25 percent for current medical students. In the past 10 years, the number of female physicians has seen the largest percentage growth, followed by American Indians, Blacks, and Hispanics. Physician executives who have vision and energy can capitalize on this demographic revolution and convert diversity into a competitive advantage once its boundaries are understood.

Plasmodium falciparum varies in its ability to induce tumor necrosis factor

Tumor necrosis factor (TNF) has a variety of protective and pathological actions in human malaria. We report that different laboratory lines of Plasmodium falciparum which were derived from a single wild isolate (IT 4/25/5) varied widely in their ability to stimulate TNF production by human mononuclear cells. In the cloned line R29 we observed that subcultures selected for high rosetting frequency gave significantly higher levels of TNF stimulation than subcultures with low rosetting frequency, indicating that TNF induction can vary within populations that have originated from a single genotype. These results raise the possibility that the clinical severity of malaria is partly determined by the TNF-inducing activity of the infecting strain of parasite.

Group work. Cope street revisited

45 Cope Street is a preventive health project working with pregnant women and young mothers aged between 16 and 25 years and their children in the inner city of Nottingham. A beacon of innovative health visiting practice, it has recently passed the fifth anniversary of its opening. Team leader Ann Rowe describes their philosophy and practice.

Black offenders from the prison system in Georgia

This secondary analysis based on a previous study by the author of 14,834 men and women in the state prison system in Georgia shows that cultural differences for youth exhibited in frequency of rule conformity by white and nonwhite inmates did not appear among the middle-aged inmates.

Ets-1 and Ets-2 protooncogene expression in theca cells of the adult mouse ovary

We have investigated the mRNA expression of the Ets-1 and Ets-2 genes in murine gonads and found expression in adult ovaries. In situ hybridization experiments show that the Ets genes are predominantly expressed in theca cells and cells of ovarian interstitium. By gel retardation experiments we detected DNA binding proteins in ovaries that specifically bind to the ETS motif, suggesting the expression of Ets or Ets-related proteins. Our results raise the possibility of Ets-2 involvement in ovarian pathology seen in patients with Down's syndrome.

Position-dependence of retinoic acid receptor-beta gene expression in the chick limb bud

Retinoic acid and 3,4-didehydroretinoic acid are metabolites of vitamin A that can induce duplications and other malformations when locally applied to the anterior margin of the chick limb bud. There is evidence that they may be natural signaling substances in the limb bud. Both compounds are thought to act by binding to ligand-dependent transcription factors that belong to the steroid/thyroid hormone nuclear receptor superfamily. In situ hybridization analyses show that in the mesenchyme of the chick wing bud between embryonic stages 20 and 27, retinoic acid receptor-beta (RAR-beta) transcripts are restricted to the proximal region of the bud and are present at highest levels in the region of the limb bud mesenchyme that contributes to the shoulder. We have performed grafting experiments in order to examine whether RAR-beta gene expression in limb bud mesenchyme cells is cell-autonomous or whether it is dependent upon the cell's position within the limb bud. When tissue from the proximal region of the stage 22 wing bud, which contains high levels of RAR-beta transcripts, was grafted to the distal tip of the bud, RAR-beta transcripts were undetectable in the graft 6 hr later. When tissue from the distal tip of the bud was grafted to a proximal site, most of the grafts exhibited a slight increase in the level of RAR-beta transcripts, which was detectable 6 hr after grafting. However, the levels of RAR-beta transcripts in these grafts never approached those found in the proximal core of the bud. These data indicate that RAR-beta gene expression in the chick wing bud is position-dependent in that it is repressed at the distal tip of the bud and partially activated by grafting distal tissue to a proximal site. However, accumulation of RAR-beta transcripts to high levels appears to be a characteristic of mesenchyme that was initially specified to form proximal structures.

In vivo and in vitro characterization of overproduced colicin E9 immunity protein

We report the overproduction of the immunity protein for the DNase colicin E9 and its characterization both in vivo and in vitro. The genes for colicin immunity proteins are normally co-expressed from Col plasmids with their corresponding colicins. In the context of the enzymatic colicins, the two proteins form a complex, thereby protecting the host bacterium from the antibiotic activity of the colicin. This complex is then released into the medium, whereupon the colicin alone translocates (through the appropriate receptor) into sensitive bacterial strains, resulting in bacterial cell death. The immunity protein for colicin E9 (Im9) has been overproduced in a bacterial host in the absence of its colicin, to enable sufficient material to be isolated for structural studies. As a prelude to such studies, the in-vivo and in-vitro properties of overproduced Im9 were analysed. Electrospray mass spectrometry verified the molecular mass of the purified protein and analytical ultracentrifugation indicated that the native protein approximates a symmetric monomer. Fluorescence-enhancement and gel-filtration experiments show that purified Im9 binds to colicin E9 in a 1:1 molar ratio and that this binding neutralizes the DNase activity of the colicin. These results lay the foundations for a full biophysical and structural characterization of the colicin E9 DNase inhibitor protein, Im9.

Development of the spatial pattern of retinoic acid receptor-beta transcripts in embryonic chick facial primordia

Retinoic acid causes a range of embryonic defects, including craniofacial abnormalities, in both birds and mammals and is believed to have a number of roles in normal development. We have previously shown that the distribution of retinoic acid receptor-beta (RAR-beta) transcripts is spatially restricted within the neural-crest-derived upper beak primordia of the chick embryo. We have now used in situ hybridisation to trace the distribution of RAR-beta transcripts during the migration of cranial neural crest cells and during formation of these primordia. RAR-beta transcripts were present in a subset of migrating neural-crest-derived cells in the head of the stage 10 embryo. These cells were situated in pathways followed by cells that migrate from the neural crest overlying the posterior prosencephalic/anterior mesencephalic region of the developing brain. Cells containing RAR-beta transcripts accumulated around the developing eyes and in the regions of the ventral head from which the upper beak primordia later develop. We mapped the distribution of RAR-beta transcripts as the facial primordia were forming, with particular reference to the development of the maxillary primordia. We found that these form in a region of the ventral head that includes the boundary between regions of high and low levels of RAR-beta transcripts. The boundary between these two groups of cells persisted as the maxillary primordia developed.(ABSTRACT TRUNCATED AT 250 WORDS)

A member of the chicken RXR family of nuclear receptors activates transcription in response to retinoic acid

The chicken cRXR nuclear receptor is a member of the steroid/thyroid hormone receptor superfamily. In this paper we show that cRXR can transactivate gene expression in response to retinoic acid, but that its sensitivity to retinoic acid is lower than that of the hRAR-beta receptor. We have also compared the ability of cRXR and hRAR-beta to respond to a panel of other retinoids. Unlike hRAR-beta, cRXR failed to respond to the naturally occurring retinoid 3,4-didehydro-retinoic acid or to the synthetic retinoid TTNPB, both of which share the ability of retinoic acid to induce digit duplications when locally applied to chick limb buds.

Note on education and self-worth among AngloAmerican, black American, and Mexican-American men in San Antonio

Data from a secondary analysis of a larger study of machismo and alcohol drinking of 481 male regular drinkers in San Antonio support the hypothesis that higher education leads to high perception of self-worth among AngloAmericans, black Americans, and Mexican-Americans.

Is 'evaluation' a dirty word?

How do we measure the important aspects of preventive health care? - what the users of the service value and what we know from experience is working. Pippa Mackeith and Ann Rowe's work at 45 Cope Street, a centre for young mothers, suggests that evaluation can be both acceptable and useful to clients, workers, managers and taxpayers.

Retinoic acid treatment alters the distribution of retinoic acid receptor-beta transcripts in the embryonic chick face

Retinoic acid is a metabolite of vitamin A that can act as a signalling molecule in a number of developmental systems. Retinoic acid is also known to be teratogenic in mammals, causing a range of defects including abnormalities in craniofacial development. Exposure of the developing chick face to retinoic acid released slowly from a bead implanted in the wing bud results in a specific facial defect, in which outgrowth of the frontonasal mass is inhibited. This results in clefting of the primary palate and absence of the upper beak. To investigate the role of nuclear retinoic acid receptors in normal and abnormal chick face morphogenesis, we isolated chick retinoic acid receptor-beta (RAR-beta) cDNA clones and probed northern blots of RNA isolated from chick embryos at stages 22, 24 and 25 and from adults. RAR-beta transcripts of 2.8 and 3.5 kb were present in several regions of the embryo, including the facial primordia, and were also present at much lower levels in adult tissues. In situ hybridisation showed that RAR-beta transcripts were present in all of the facial primordia at embryonic stages 20, 24 and 28, but that their distribution was not uniform. Transcripts were abundant in the lateral nasal processes, at the edges and corners of the frontonasal mass and in the anterior part of the maxillary primordia. Lower levels were present elsewhere. Treatment of stage 20 embryos with retinoic acid altered the distribution of RAR-beta transcripts in the maxillary primordia, such that high levels of transcripts were present throughout, rather than being confined to the anterior part. This change was detectable at stage 24, before any alterations in the morphology of the facial primordia were apparent. By stage 28, when the morphology of the facial primordia was clearly abnormal, there were more widespread changes in the distribution of RAR-beta transcripts. These results show that RAR-beta transcripts are particularly concentrated in regions of the primordia that give rise to the upper beak, the development of which is specifically affected by retinoic acid. In addition, they demonstrate that retinoic acid can induce changes in the pattern of expression of RAR-beta transcripts in vivo.

A member of the RXR nuclear receptor family is expressed in neural-crest-derived cells of the developing chick peripheral nervous system

Retinoic acid (RA) affects differentiation and morphogenesis in various developmental systems and is believed to act through nuclear RA receptors that belong to the steroid/thyroid hormone family of ligand-binding transcription factors. Three closely related receptors, RAR-alpha, -beta and -gamma, with distinct expression patterns, have been identified and a fourth receptor, hRXR-alpha, which responds to RA but which has low homology to RAR-alpha, -beta and -gamma, was recently discovered. Here we report the isolation of a cDNA clone encoding a chicken homologue of hRXR-alpha (cRXR) and show that a cRXR transcript of 2.5 kb is expressed in a range of embryonic chick tissues. By in situ hybridization to sections from stage 24 and stage 27 chick embryos, we show that cRXR transcripts are expressed at high levels in the liver and in elements of the developing peripheral nervous system derived from the neural crest, including dorsal root ganglia, cranial ganglia, enteric ganglia and peripheral nerve tracts. At stage 16, in the posterior trunk region, cRXR transcripts are expressed by cells in the neural crest and in neural crest cells migrating into the sclerotome, indicating that neural crest cells express cRXR transcripts before overt differentiation into peripheral nervous tissue. This distribution suggests a novel role for RA in the developing peripheral nervous system, mediated by cRXR. In addition, it identifies cRXR as a marker for a specific population of neural-crest-derived cells.

Ectodermal inhibition of cartilage differentiation in micromass culture of chick limb bud mesenchyme in relation to gene expression and cell shape

Ectoderm inhibits the formation of cartilage by chick wing bud mesenchyme in micromass culture. This suggests that the pattern of cartilage formation in the limb bud may result from a restriction of cartilage cell differentiation to the limb bud core as cells leave the progress zone. We have used in situ hybridization to investigate whether ectodermal inhibition in micromass culture occurs at the level of gene transcription. We found that ectoderm completely inhibited the accumulation of cartilage-specific type II collagen transcripts in the mesenchyme cells, whilst the level of type I collagen transcripts was unaffected. Morphometric analysis of electron micrographs revealed that inhibition of chondrogenesis in micromass culture was not preceded by cell flattening. In fact, a rounded cell shape was found not to be a prerequisite for cartilage cell differentiation in micromass.

The structure and expression of a hybrid homeotic gene

We describe the structure and expression of an exceptional bithorax complex mutation, C1. This deletion mutation removes major portions of both the Ultrabithorax (Ubx) and abdominal-A (abd-A) protein coding regions, yet retains many of the functions normally executed by these genes. We show that the ends of the C1 deletion map to analogous positions within the Ubx and abd-A transcription units, and that the deletion chromosome gives rise to a set of novel fusion transcripts that may encode hybrid abd-A/Ubx proteins. These fusion products are transcribed from the abd-A promoter, but exhibit a novel spatial pattern of expression that combines aspects of the normal Ubx and abd-A distributions. This pattern provides evidence for the existence of regulatory elements located in the 3' region of the Ubx transcription unit that can act on the abd-A promoter at a distance of at least 20 kb.