Detection of threonine structural changes upon formation of the M-intermediate of bacteriorhodopsin: evidence for assignment to Thr-89

The behavior of threonine residues in the bacteriorhodopsin (bR) photocycle has been investigated by Fourier transform infrared difference spectroscopy. L-Threonine labeled at the hydroxyl group with 18O (L-[3-(18)O]threonine) was incorporated into bR and the bR-->M FTIR difference spectra measured. Bands are assigned to threonine vibrational modes on the basis of 18O induced isotope frequency shifts and normal mode calculations. In the 3500 cm-1 region, a negative band is assigned to the OH stretch of threonine. In the 1125 cm-1 region, a negative band is assigned to a mixed CH3 rock/CO stretch mode. The frequency of both these bands indicates the presence of at least one hydrogen bonded threonine hydroxyl group in light adapted bR which undergoes a change in structure by formation of the M intermediate. Spectral changes induced by the substitution Thr-89-->Asn but not Thr-46-->Asn or Asp-96-->Asn are consistent with the assignment of these bands to Thr-89. These results along with another related study on the mutant Thr-89-->Asn indicate that the active site of bR includes Thr-89 and that its interaction with the retinylidene Schiff base and Asp-85 may play an important role in regulating the color of bacteriorhodopsin and the transfer of a proton to the Schiff base.

(Re)constructing relationships with grandparents: a turning point analysis of granddaughters' relational development with maternal grandmothers

This study explores how granddaughters account for the development of their relationships with their maternal grandmothers. The retrospective interviewing technique was used to elicit turning points in their relational histories. Analysis of the turning point content revealed several different types of turning points that reflected both normative and idiosyncratic events. Increases in relational closeness resulted from decreases in geographic separation, engaging in shared activities, deaths or serious illnesses in the family, and family disruptions. Decreases in closeness were associated with negative experiences with the grandmother, increases in geographic separation, and the transition to college. Granddaughters reported that turning points related to death or serious illness and participation in shared activities were the most significant ones in their relationships with maternal grandmothers.

Augmented therapy of extensive Hodgkin's disease: radiation to known disease or prolongation of induction chemotherapy did not improve survival--results of a Cancer and Leukemia Group B study

PURPOSE

This prospective randomized trial in extensive untreated Hodgkin's disease was undertaken to assess the potential benefit of augmented therapy (12 months chemotherapy or radiation to known disease) compared to standard 6 months chemotherapy.

PATIENT AND METHODS

A total of 258 patients, mostly Stage IV, were randomized to four treatment regimens consisting of six cycles of CCNU, vinblastine, procarbazine, and prednisone (CVPP); 12 cycles of CVPP; six cycles of CVPP followed by 25 Gy radiotherapy; or three cycles CVPP, 25 Gy radiotherapy, and three cycles CVPP.

RESULTS

Complete remissions were achieved in 65% of all patients. A 58% overall 5-year survival rate was obtained. Relapses in irradiated areas of known disease occurred in only 6% of responding patients. There was, however, no statistical difference in response frequency, disease-free survival, or overall survival among the four regimens. Elderly patients responded less frequently.

CONCLUSION

While radiotherapy provided control of local (known) disease, no impact on overall survival was apparent. Likewise, doubling the duration of chemotherapy did not improve response or survival. Augmentation of therapy with either radiotherapy or more chemotherapy in this study was of no benefit compared to the standard 6 months of treatment.

The simplest walking model: stability, complexity, and scaling

We demonstrate that an irreducibly simple, uncontrolled, two-dimensional, two-link model, vaguely resembling human legs, can walk down a shallow slope, powered only by gravity. This model is the simplest special case of the passive-dynamic models pioneered by McGeer (1990a). It has two rigid massless legs hinged at the hip, a point-mass at the hip, and infinitesimal point-masses at the feet. The feet have plastic (no-slip, no-bounce) collisions with the slope surface, except during forward swinging, when geometric interference (foot scuffing) is ignored. After nondimensionalizing the governing equations, the model has only one free parameter, the ramp slope gamma. This model shows stable walking modes similar to more elaborate models, but allows some use of analytic methods to study its dynamics. The analytic calculations find initial conditions and stability estimates for period-one gait limit cycles. The model exhibits two period-one gait cycles, one of which is stable when 0 < gamma < 0.015 rad. With increasing gamma, stable cycles of higher periods appear, and the walking-like motions apparently become chaotic through a sequence of period doublings. Scaling laws for the model predict that walking speed is proportional to stance angle, stance angle is proportional to gamma 1/3, and that the gravitational power used is proportional to v4 where v is the velocity along the slope.

Local anaesthetic toxicity in a pregnant patient undergoing lignocaine-induced intravenous regional anaesthesia

A pregnant patient at 38 weeks' gestation developed symptoms of local anaesthetic toxicity following intravenous regional anaesthesia (IVRA) for hand surgery, using a standard dose of lignocaine. Reports suggest that a number of factors, both physiological and pharmacological, combine to increase the likelihood of local anaesthetic (LA) toxicity in pregnancy despite employment of a conventional "safe" IVRA technique. It is suggested that for IVRA, pregnant patients are premedicated with a benzodiazepine, the tourniquet time is increased and the concentration of LA is decreased to reduce the risks of LA toxicity.

Effects of dietary fatty acids on DU145 human prostate cancer cell growth in athymic nude mice

The purpose of this study was to examine the effects of diets containing different unsaturated fatty acids (FAs) on DU145 human prostate cancer cell growth in nude mice. In Experiment 1, groups of 25 mice were fed 23% (wt/wt) fat diets containing 18% corn oil (CO)-5% linseed oil (18:2n-6 FA-rich), 18% linseed oil (LO)-5% CO (18:3n-3 FA-rich), or 18% menhaden oil (MO)-5% CO (20:5 and 22:6n-3 FA-rich), and seven days later they were injected subcutaneously with 1 x 10(6) DU145 cells. The diets were continued for six weeks. The growth rates and final weights of tumors from the 18% CO-5% LO and 18% LO-5% CO mice were similar; there was a 30% reduction in tumor growth in the 18% MO-5% CO group (p < 0.001). The tumor phospholipid FA patterns suggested that the inhibitory effect of the high-MO diet was due, at least in part, to a reduction of arachidonic acid available for prostaglandin biosynthesis. In Experiment 2, groups of 25 mice were injected with 5 x 10(5) or 1 x 10(6) DU145 cells directly into the prostate gland and fed a high-fat linoleic acid (n-6 FA)-rich or a low-fat diet for 10 weeks. At necropsy, macroscopic cancers and microscopic intraprostatic tumors were evaluated. When the initial tumor load was 1 x 10(6) cells, all but 7 of the 50 mice had developed large macroscopic tumors; the mean tumor weight in the high-fat group was twice that in the low-fat group (p = 0.047). A stimulatory effect of dietary n-6 FA on DU145 prostate cancer cell growth may require a critical initial tumor cell mass.

Starvation-induced genes of the tomato pathogen Cladosporium fulvum are also induced during growth in planta

The pathogenicity of fungal pathogens is presumably dependent on genes that are expressed during infection. In order to isolate such genes from the tomato pathogen Cladosporium fulvum, and to test the hypothesis that starvation-induced genes are also plant induced, a cDNA library was prepared from mycelia grown in a defined medium and then transferred to a starvation medium. The library was then screened with cDNA prepared from starved and replete fungal mycelium. Five unique, differentially expressed cDNAs were isolated from 1,000 clones screened. Northern (RNA) hybridization confirmed that all five were starvation induced. Interestingly, all five were also found to be plant induced. The identity of two of the clones was indicated by partial DNA sequencing as alcohol and aldehyde dehydrogenase. The observed correlation between starvation induction and plant induction in discussed.

Copper supplementation of adult men: effects on blood copper enzyme activities and indicators of cardiovascular disease risk

In rats, copper deficiency leads to low copper metalloenzyme activity, high serum cholesterol, and cardiovascular lesions. In humans, moderately low copper intake may be common, but the consequences remain largely uncertain. The present study examined the effects of copper supplementation (2 mg/d for 4 weeks in a copper/placebo crossover design) in 20 adult men with moderately high plasma cholesterol. End-point measurements were three copper enzyme activities, erythrocyte superoxide dismutase (SOD), plasma ceruloplasmin (Cp), and plasma diamine oxidase (DAO), and three parameters related to the risk of cardiovascular disease (CVD), plasma cholesterol, plasma lipoprotein (a) [Lp(a)], and lag times for very-low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) oxidation in vitro. Although copper had no significant effects on any parameter for the entire study group, it did significantly increase two enzyme activities (SOD and DAO), as well as lipoprotein oxidation lag times, in 10 subjects in the lower half of a median split for precopper values. Thus, copper supplementation appeared to influence some types of measurements in subjects beginning with less than median values.

Variability in cytokine and cell adhesion molecule staining in arthroscopic synovial biopsies: quantification using color video image analysis

OBJECTIVE

To investigate the variability in immunostaining for cytokines and cell adhesion molecules using multiple arthroscopically directed synovial biopsies from within a rheumatoid knee joint, quantitated by color video image analysis.

METHODS

Needle arthroscopic biopsies were taken from multiple sites (4-7 sites) around a knee joint in 8 patients with rheumatoid arthritis (RA). In 5 patients, immunoperoxidase staining for the cytokines tumor necrosis factor alpha (TNF-alpha), interleukin 8 (IL-8), and IL-1beta as well as the IL-1 receptor antagonist protein (IL-1ra) was performed. In 3 patients, immunoperoxidase staining for the cell adhesion molecules E-selectin (CD62E), P-selectin (CD62P), intercellular adhesion molecule 1 (ICAM-1, CD54), and platelet endothelial cell adhesion molecule (PECAM, CD31) was performed. Immunostaining was quantified using color video image analysis.

RESULTS

The overall probability of paired biopsies from the same RA knee joint being significantly different from each other due to sampling variation was at most 22% for cytokine staining (usually less than 10%). There were no significant differences between intrabiopsy and interbiopsy variability for cell adhesion molecule staining of the sublining and vessels.

CONCLUSION

The variability in cytokine and cell adhesion molecule staining within any single biopsy usually reflects the variability between biopsies taken from different sites in the same rheumatoid joint when the immunostaining is quantified using color video image analysis. Therefore, only a small number of synovial biopsies are required to accurately determine the cytokine and cell adhesion molecule expression in a single joint.

Granddaughters' accounts of the influence of parental mediation on relational closeness with maternal grandmothers

This study explores granddaughters' reports of the nature and impact of parental mediation on the development of their feelings of closeness toward their maternal grandmothers. Results from close-ended questions assessing granddaughters' perceptions of parental mediation and relational closeness indicated that closeness was predicted by mediation involving: visits alone with grandmothers, the absence of criticism of grandmothers, communication indicating the grandmothers were important persons, and less influence on conversations or activities. Qualitative analysis of granddaughters' accounts of the influence of parents illustrated what they perceived to be important issues in mediation. Additionally, accounts revealed the role of other family members in the relationship mediation process.

Are faces of different species perceived categorically by human observers?

What are the species boundaries of face processing? Using a face-feature morphing algorithm, image series intermediate between human, monkey (macaque), and bovine faces were constructed. Forced-choice judgement of these images showed sharply bounded categories for upright face images of each species. These predicted the perceptual discrimination boundaries for upright monkey-cow and cow-human images, but not human-monkey images. Species categories were also well-judged for inverted face images, but these did not give sharpened discrimination (categorical perception) at the category boundaries. While categorical species judgements are made reliably, only the distinction between primate faces and cow faces appears to be categorically perceived, and only in upright faces. One inference is that humans may judge monkey faces in terms of human characteristics, albeit distinctive ones.

Expression of biologically active human insulin-like growth factor-I following intramuscular injection of a formulated plasmid in rats

Recent evidence has shown that insulin-like growth factor-I (IGF-I) plays an important role in the development, maintenance, and regeneration of peripheral nerves and skeletal muscle. IGF-I offers the potential to treat neuromuscular diseases in humans. We have developed a nonviral gene therapy method to express and produce localized and sustained therapeutic levels of IGF-I within target muscles by intramuscular injection of formulated plasmids. The purpose of the present study was to demonstrate that intramuscular injection of a plasmid encoding human IGF-I (hIGF-I) and engineered to restrict expression to skeletal muscle produces sustained local concentrations of biologically active hIGF-I. Normal rats received a single intramuscular injection of plasmids formulated as a complex with polyvinylpyrrolidone (PVP). Results show that hIGF-I mRNA and hIGF-I protein were detectable in the injected muscles for the duration of the study (28 days), whereas the hIGF-I protein was not detected in blood. Biological activity of hIGF-I was determined by immunodetection of a nerve-specific growth-associated protein, GAP-43, an indicator of motor neuron sprouting. Placement of human growth hormone (hGH) 3' untranslated region enhanced GAP-43 staining, probably due to improved secretion of hIGF-I. Enhanced immunoreactivity of GAP-43 was observed in muscles injected with the formulated hIGF-I plasmid when compared to controls. These results demonstrate that intramuscular injection of hIGF-I plasmid formulated as a complex with PVP produces a localized and sustained level of biologically active hIGF-I.

The molecular mechanisms of term and preterm labor: recent progress and clinical implications

Current tocolytic protocols rely largely on the use of beta-mimetics to induce myometrial quiescence and delay delivery. Unfortunately, the rapid transplacental passage and poor receptor specificity of the commonly used beta-mimetics results in widespread activation of intrauterine and extrauterine beta 1 and beta 2 receptors. The use of beta-mimetics is associated with a range of well-recognized and potentially dangerous side effects for mother and fetus. The value of continued use of beta-agonists after obtaining uterine quiescence also has been the subject of recent debate. In this article we have attempted to explore the biochemical and molecular rationale for the use of alternative therapeutic modalities in the treatment and prevention of PTL. In the light of the current view that the term "preterm labor" covers a considerable diversity of causes, we propose that a range of treatment regimes should be chosen on the basis of the diagnosis and classification of the patient according to the their particular condition. Although the measurement of several biochemical parameters have been suggested to be of use in predicting PTL, we believe that a panel of diagnostic indicators (e.g., free or total CRH, IL-6, extracellular matrix proteases, fetal fibronectin) is more likely to provide useful diagnostic information on which appropriate treatment modalities can be selected (Table 1). Because of the complex and interactive nature of the mechanisms operating within the intrauterine environment to regulate myometrial activation and uterotonin production, we speculate that a combination of tocolytics, anti-inflammatory agents, uterotonic antagonists, and receptor blockers is likely to be more effective than a monotherapeutic approach, which focuses on only one facet of the process of uterine activation for pharmacologic intervention. For example, the use of antibiotics, PGHS inhibitors, and/or beta-mimetics might be an appropriate first line of treatment for infection-associated PTL in extreme prematurity. If it is successful, this treatment might be followed by longer term use of a progestagen and/or NO donor to maintain myometrial quiescence until closer to term. Alternatively, use of progesterone or oxytocin antagonists may be effective in augmenting the actions of beta-mimetics while reducing their side effects, whereas other combinations may be useful as long-term prophylactics in women with a high risk of developing PTL. Improvements continue in our diagnostic ability to correctly identify the different causes of preterm labor. We anticipate that careful selection of differing combinations of therapeutic options will result in significant reductions in the morbidity, mortality, and healthcare costs associated with preterm birth.

Primary pulmonary hypertension in a patient with CD8/T-cell large granulocyte leukemia: amelioration by cladribine therapy

We report a case of primary pulmonary hypertension in an adult man with CD8/T-cell large granulocyte leukemia. Successful treatment of his leukemia with cladribine resulted in dramatic and sustained improvement of his pulmonary hypertension.

Autism and celiac disease: failure to validate the hypothesis that a link might exist

Autism is a heterogeneous condition and the possible pathogenic role of several different factors has been postulated. Association between celiac disease and neurological manifestations such as drug resistant epilepsy and cerebral calcifications is well known. Some authors in the past also reported the existence of a linkage with autism. On the basis of these observations, we have evaluated 120 patients with celiac disease diagnosed at the Pediatric Clinic of the University of Catania, Italy, in order to identify behavioral problems and autistic features: there were 20 controls for this part of the study. At the same time, AGA and AEMAb were assayed in 11 patients with infantile autism and 11 age- and sex-matched controls. No celiac case was detected among the group of autistic patients and, although two of them had slightly increased levels of AGA IgG and AEMAb, subsequent antibodies determinations and jejunal biopsies gave normal results. Moreover none of the celiac patients had a positive DSM-III-R test for infantile autism.

Threonine-89 participates in the active site of bacteriorhodopsin: evidence for a role in color regulation and Schiff base proton transfer

Bacteriorhodopsin (bR) functions as a light-driven proton pump in the purple membrane of Halobacterium salinarium. A major feature of bR is the existence of an active site which includes a retinylidene Schiff base and amino acid residues Asp-85, Asp-212, and Arg-82. This active site participates in proton transfers and regulates the visible absorption of bacteriorhodopsin and its photointermediates. In this work we find evidence that Thr-89 also participates in this active site. The substitution Thr-89 --> Asn (T89N) results in changes in the properties of the all-trans retinylidene chromophore of light-adapted bR including a redshift of the visible lambda(max) and a downshift in C=N and C=C stretch frequencies. Changes are also found in the M and N intermediates of the T89N photocycle including shifts in lambda(max), a downshift of the Asp-85 carboxylic acid C=O stretch frequency by 10 cm(-1), and a 3-5-fold decrease in the rate of formation of the M intermediate. In contrast, the properties of the 13-cis retinylidene chromophore of dark-adapted T89N as well as the K and L intermediates of the T89N photocycle are similar to the wild-type bacteriorhodopsin. These results are consistent with an interaction of the hydroxyl group of Thr-89 with the protonated Schiff base of light-adapted bR and possibly the N intermediate but not the 13-cis chromophore of dark-adapted bR or the K and L intermediates. Thr-89 also appears to influence the rate of Schiff base proton transfer to Asp-85 during formation of the M intermediate, possibly through an interaction with Asp-85. In contrast, the hydroxyl group of Thr-89 is not obligatory for proton transfer from Asp-96 to the Schiff base during formation of the N intermediate.

The levonorgestrel-releasing intrauterine device: a wider role than contraception

The Levonorgestrel-releasing intrauterine device (LNG IUD) provides excellent contraception; it may reduce the rate of pelvic inflammatory disease (PID) and ectopic pregnancy compared to other 'modern' copper releasing IUDs; it can safely be used in the puerperium for breast-feeding mothers, and it significantly reduces menstrual blood loss and pain. While it was developed primarily as a contraceptive, its potential role in managing heavy and painful menstruation and the symptoms of the climacteric may eventually be just as important. Amongst developed countries New Zealand and Australia have some of the highest hysterectomy rates. By the age of 50 years 1 in 4 women in New Zealand and 1 in 5 women in Australia will have had a hysterectomy (A,B). In New Zealand 90% of these are performed for heavy menstrual bleeding and fibroids (A). The LNG IUD has been shown to be effective treatment for both these conditions and its introduction to New Zealand and Australia would offer women an additional choice beyond surgery.

Chicken insulin-like growth factor binding protein (IGFBP)-5: conservation of IGFBP-5 structure and expression during evolution

A complementary DNA (cDNA) clone encoding chicken insulin-like growth factor binding protein-5 (cIGFBP-5) was isolated. The nucleotide sequence of the 1236-bp clone encodes a mature polypeptide of 251 amino acids with a calculated molecular weight of approximately 28.2 kDa. The deduced amino acid sequence is 83% identical to human IGFBP-5. Labeled cIGFBP-5 cDNA detected a single mRNA transcript of approximately 6 kb by Northern blot analysis of various tissues obtained from embryonic and 6 weeks post-hatch chickens; interestingly, adult heart showed an approximately 10-fold increase in cIGFBP-5 mRNA relative to embryonic heart. The pattern of IGFBP-5 mRNA expression in chicken tissues was similar to that found in mammals during fetal and extrauterine life. In addition, IGFBP-5 mRNA was abundant in primary cultures of chicken myoblasts throughout in vitro differentiation and fusion. The conservation of IGFBP-5 primary structure and expression pattern across vertebrate species suggests conservation of important functions during evolution, particularly in muscle differentiation.