Tests for detecting degradation of gelatin: comparison of five methods.

Five methods for detecting degradation of gelatin by bacteria were compared. These were liquefaction in nutrient broth, hydrolysis in nutrient agar, hydrolysis of charcoal gelatin strips, degradation of the gelatin on strips of photographic film, and alkalinization of gelatin agar. Degradation of photographic film is a rapid and convenient method but, like hydrolysis of gelatin in broth and in agar, may fail to detect weakly positive strains of bacteria. Alkalinization of gelatin in an agar medium is a convenient and sensitive method to detect degradation of gelatin, particularly by Pseudomonas fluorescens, but this method may not be applicable to some species.     

Coping and catastrophizing in chronic pain: a psychometric analysis and comparison of two measures

We analyzed and compared the psychometric properties of two measures of strategiesfor coping with pain:The Coping Strategies Questionnaire (CSQ) and the Cognitive Coping Strategies Inventory (CCSI). The CSQ and CCSI were repeatedly administered to 30 chronic pain patients. Several subscales of both measures showed inadequate internal consistency, and test-retest (one week interval) reliability lower than 0.7. For each inventory, moderate to strong intercorrelations between several subscales were observed. The Catastrophizing subscale was the only subscale for which there was clear evidence of construct validity. Results indicated that both measures showed similar psychometric difficulties, and question the construct validity of subscales other than Catastrophizing. Catastrophizing, however, more closely reflects appraisal processes than a coping strategy per se. We suggest that measures that use more parsimonious and empirically derived coping strategy subscales and that also assess appraisal factors would assist in advancing our understanding of coping with chronic pain.     

Genotypic analysis of sequential genital herpes simplex virus type 1 (HSV-1) isolates of patients with recurrent HSV-1 associated genital herpes

Clinical recurrences of Herpes simplex virus type 1 (HSV-1)-associated genital herpes are thought to be caused by reactivation of latent endogenous HSV-1. However, the possibility of reinfection with exogenous HSV-1 cannot be excluded. This study aimed to determine the incidence of genital HSV-1 superinfection in patients by investigating the genotype of sequential HSV-1 isolates obtained from the same anatomical site of patients with clinical recurrences of genital HSV-1 recurrent genital herpes. Sequential genital HSV-1 isolates were genotyped by PCR amplification of the hypervariable regions located within the HSV-1 genes US1 and US12. Whereas the sequential HSV-1 isolates in 11 of the 13 patients studied had the same genotypes, the sequential isolates of 2 patients showed a different genotype. The data suggest that HSV-1-induced recurrent genital herpes can be associated with genital reinfection with an exogenous HSV-1 strain.     

Vascular studies with histamine in vitro

In vitro studies to analyse the pharmacology of histamine-induced dilatation of resistance vessels in rat hindquarters have been made. Histamine caused dose-dependent dilatation of resistance vessels over the concentration range 10^–9 to 10^–6 mol. Responses to histamine were antagonized by cimetidine but not by mepyramine. Dimaprit also caused vasodilatation. Responses to dimaprit were inhibited by cimetidine 10^–6 to 10^–5 M. A pA₂ of 6.43 (6.11–6.75, 95% confidence limits) was calculated for cimetidine in the resistance vessels of the hindquarters.     

Lymphatic endothelial cell identity is reversible and its maintenance requires Prox1 activity

The activity of the homeobox gene Prox1 is necessary and sufficient for venous blood endothelial cells (BECs) to acquire a lymphatic endothelial cell (LEC) fate. We determined that the differentiated LEC phenotype is a plastic, reprogrammable condition that depends on constant Prox1 activity for its maintenance. We show that conditional down-regulation of Prox1 during embryonic, postnatal, or adult stages is sufficient to reprogram LECs into BECs. Consequently, the identity of the mutant lymphatic vessels is also partially reprogrammed as they acquire some features typical of the blood vasculature. siRNA-mediated down-regulation of Prox1 in LECs in culture demonstrates that reprogramming of LECs into BECs is a Prox1-dependent, cell-autonomous process. We propose that Prox1 acts as a binary switch that suppresses BEC identity and promotes and maintains LEC identity; switching off Prox1 activity is sufficient to initiate a reprogramming cascade leading to the dedifferentiation of LECs into BECs. Therefore, LECs are one of the few differentiated cell types that require constant expression of a certain gene to maintain their phenotypic identity.     

Oocyte morphology predicts outcome of intracytoplasmic sperm injection

To examine the influence of cytoplasmic morphology on the success rate of intracytoplasmic sperm injection (ICSI), the morphology of 837 metaphase II oocytes was assessed after cumulus stripping. The main abnormalities detected were excessive granularity, cytoplasmic inclusions such as vacuoles, smooth endoplasmic reticulum clustering and refractile bodies. Microinjection was performed in 538 oocytes with normal cytoplasm, 142 out of 161 with excessive granularity and 112 out of 138 with cytoplasmic inclusions. Very poor oocytes were not injected. No difference was found in fertilization rate. The embryos achieved cleaved normally and a similar number of good quality embryos among the three groups was noted. The outcome of transfer of embryos derived solely from normal oocytes (group A: 72 patients, 183 embryos) was compared with those from oocytes with cytoplasmic abnormalities (group B: 34 patients, 85 embryos). In group A, 17 clinical pregnancies (24% per patient, implantation rate 10%) were established. In group B, only one clinical pregnancy (3% per patient, implantation rate 1%) was established, from the transfer of embryos derived from oocytes with homogeneous granularity of the cytoplasm. No pregnancy resulted following the transfer of embryos from eggs with cytoplasmic inclusions. The difference was statistically significant. The outcome of ICSI is dependent on the quality of the oocytes retrieved. Normal fertilization and early embryo development were achieved in oocytes with abnormal cytoplasm morphology, but the resulting embryos failed to demonstrate the same implantation potential as those derived from oocytes with normal cytoplasm.      

Growth hormone as an early embryonic growth and differentiation factor

In this review we consider the evidence that growth hormone (GH) acts in the embryo as a local growth, differentiation, and cell survival factor. Because both GH and its receptors are present in the early embryo before the functional differentiation of pituitary somatotrophs and before the establishment of a functioning circulatory system, the conditions are such that GH may be a member of the large battery of autocrine/paracrine growth factors that control embryonic development. It has been clearly established that GH is able to exert direct effects, independent of insulin-like growth factor-I (IGF-I), on the differentiation, proliferation, and survival of cells in a wide variety of tissues in the embryo, fetus, and adult. The signaling pathways behind these effects of GH are now beginning to be determined, establishing early extrapituitary GH as a bona fide developmental growth factor.     

Modeling of longitudinal academic achievement scores after pediatric traumatic brain injury

In a prospective longitudinal study, academic achievement scores were obtained from youth 5 to 15 years of age who sustained mild-moderate (n = 34) or severe (n = 43) traumatic brain injuries (TBI). Achievement scores were collected from baseline to 5 years following TBI and were subjected to individual growth curve analysis. The models fitted age at injury, years since injury, duration of impaired consciousness, and interaction effects to Reading Decoding, Reading Comprehension, Spelling, and Arithmetic standard scores. Although scores improved significantly over the follow-up relative to normative data from the standardization sample of the tests, children with severe TBI showed persistent deficits on all achievement scores in comparison to children with mild-moderate TBI. Interactions of the slope and age parameters for the Arithmetic and Reading Decoding scores indicated greater increases over time in achievement scores of the children injured at an older age, but deceleration in growth curves for the younger children with both mild-moderate and severe TBI. These results are compatible with the hypothesis that early brain injuries disrupt the acquisition of some academic skills. Hierarchical regression models revealed that indexes of academic achievement obtained 2 years following TBI had weak relations with the duration of impaired consciousness and socioeconomic status. In contrast, concurrent cognitive variables such as phonological processing and verbal memory accounted for more variability in academic scores. Given the significant and persistent decrement in basic academic skills in youth with severe TBI, it is clear that head-injured youth require intensive, long-term remediation and intervention not only of the academic skills themselves, but also of those cognitive abilities that support the development and maintenance of reading and math.     

A comprehensive analysis of verbal fluency deficit in geriatric schizophrenia.

Deficits in verbal fluency are common in schizophrenia and may provide keys to some of the abnormalities in the semantic system in schizophrenia. While a number of studies have outlined the severity and implications of verbal fluency deficits in younger schizophrenia patients, these findings have not yet been extended to older patients with schizophrenia. In this study, 392 older (age >/= 50) patients with schizophrenia were administered phonological and semantic (i.e., category) fluency examinations, as well as tests of learning, memory, language, and praxic skills, and rated for clinical symptoms and functional status. When compared to normative standards, 82% of the patients were impaired in semantic fluency and 83% were impaired in phonological fluency. Both semantic and phonological fluency impairment were significantly correlated with other cognitive variables, total scores on the functional status measure, and with the social and self-care subscales. Scores were uncorrelated with the severity of psychosis, but were correlated with the severity of negative symptoms. Furthermore, the severity of poverty of speech (a clinical measure of verbal underproductivity) was moderate in magnitude and failed to enter as a predictor of verbal fluency, indicating that impaired fluency scores are not simply an artifact of general underproductivity or mutism. The findings support conclusions from studies with younger schizophrenia patients that suggest that verbal fluency impairment is a consequence of a disorganized semantic system. Verbal fluency impairment remains common and functionally relevant in schizophrenia patients in late life.