Evaluating behavioral interventions for HIV prevention

We report a case of primary amyloidosis affecting the kidney and presenting as a renal infarction on computed tomography and ultrasound examination. To our knowledge, it is the first case in the radio-logical literature with these imaging characteristics.     

Panic and panic disorder in the United States

OBJECTIVES: Shift work and rapid travel across several time zones leads to desynchronization of internal circadian rhythms from the external environment and from each other with consequent problems of behaviour, physiology and performance. Field studies of travellers and shift workers are expensive and difficult to control. This investigation concerns the simulation of such rhythm disturbance in a laboratory environment. The main objectives are to assess the ability of controlled exposure to moderately bright light and darkness/sleep to delay circadian rhythms in volunteers without environmental isolation and, secondly, to evaluate the use of different indices of melatonin (MT) secretion together with self-rated alertness as marker rhythms. PATIENTS: Six normal volunteers aged 22-26 years (mean +/- SD 24.3 +/- 1.4). DESIGN: Subjects were exposed to the following periods of moderately bright light (1200 lux) on three consecutive days in early December 1991: Day (D)1: 2000-0200 h, D2: 2200-0400 h and D3: 2400-0600 h. Each period was followed by 8 hours of darkness (< 1 lux). Hourly blood, sequential 4-hourly urine (8-hourly when asleep) and hourly saliva (except when asleep) samples were taken throughout a 24-hour period on D0 (baseline), D4 (1 day post-light treatment) and D7 (4 days post-light treatment). During waking hours, subjective alertness was rated every 2 hours on a visual analogue scale. MEASUREMENTS: MT was measured in plasma and saliva, and its metabolite, 6-sulphatoxymelatonin (aMT6s), was measured in urine. MT, aMT6s and alertness scores were analysed by ANOVA and a cosinor analysis program. RESULTS: A delay shift was present in the aMT6s, plasma MT and salivary MT rhythms (degree of shift: 2.67 +/- 0.3 h (P < 0.001, n = 5); 2.35 +/- 0.29 h (P < 0.001, n = 6); and 1.97 +/- 0.32 h (P < 0.01, n = 6), mean +/- SEM, respectively) 1 day post-light treatment compared to baseline. Adaptation to the initial phase position was apparent by the 4th post-treatment day. Significant correlations were obtained between plasma MT onset (degree of shift: 3.12 +/- 0.74 h (P < 0.001, n = 6, mean +/- SEM)) and the acrophases (calculated peak times) of plasma MT (P < 0.001), salivary MT (P < 0.05) and urinary aMT6s (P < 0.01). A significant phase delay in the alertness rhythm was also evident 1 day post-treatment (3.08 +/- 0.67 h (P < 0.01, n = 6, mean +/- SEM)) with adaptation by the 2nd post-treatment day. CONCLUSIONS: This study suggests that these methods of determining MT secretion are comparable and give reliable assessments of the MT circadian phase position even after a phase-shift. Significant phase-shifts of similar magnitude can be induced in both MT and alertness rhythms using moderate intensity bright light at night.     

Effect of multiple sclerosis materials on polymorphonuclear neutrophils of mice

Necrotizing enterocolitis (NEC) usually occurs in low birth weight infants who have had perinatal stress, and the mortality remains significant. There are a few reports of NEC in the postoperative period, especially in young infants. Nine neonates developed NEC following operations and form the basis of this report. The interval between operation and the diagnosis of NEC varied from 3 days to 4 mo. The surgical lesions included one case each of esophageal atresia, tetralogy of Fallot, supralevator rectal atresia with rectourethral fistula, and multiple intestinal atresias. Three babies had gastroschisis and two had "apple peel" intestinal atresia. Only 3 of the 9 survived. The usual clinical findings of NEC, abdominal distention, bile stained gastric residuals and diarrhea (with or without blood), can occur in the postoperative period without NEC and are, therefore, not reliable diagnostic signs. Significant changes in the clinical course of these babies occurred from 7 hr to 5 days before the diagnosis was established. In these patients the roentgen findings that established the diagnosis of NEC included intestinal ileus, pneumatosis intestinalis, and portal vein gas. Pneumatosis intestinalis and portal vein gas were the most reliable diagnostic signs, but appeared relatively late in the course of the disease. In one case pneumatosis was seen only in retrospect. None of the patients had definite pneumoperitoneum. Awareness of NEC as a potential postoperative complication may result in early recognition, treatment and survival.     

Non-hierarchical logistic models and case-only designs for assessing susceptibility in population-based case-control studies

Mechanisms for the abnormal copper (Cu) accumulation in the liver of LEC rats were examined using primary cultured liver parenchymal cells prepared from mutant LEC rats and those from control LEA rats (original strain). The Cu and metallothionein (MT) mRNA levels in the liver of LEC rats were caused to decrease to the same levels as those of LEA rats by removing Cu in vivo selectively with tetrathiomolybdate. Cu was taken up by LEC rat cells to the same extent as LEA rat cells by exposure to low medium Cu and to a higher extent by exposure to high medium Cu, while the MT mRNA level in LEC rat cells increased dose-dependently at a much higher rate than that in LEA rats. MT mRNA levels in both cells were comparable by exposure to cadmium, zinc and dexamethasone. The results indicate that expression of MT mRNA is selectively enhanced by Cu in LEC cells despite the fact that uptake of Cu is comparable with normal cells.     

Diagnosis of African horsesickness

African horsesickness (AHS) is a very serious, non-contagious disease of horses and other solipeds caused by an arthropod-borne orbivirus of the family Reoviridae. The epizootic nature of the disease makes rapid, accurate diagnosis of AHS absolutely essential. Currently, diagnosis of AHS is based on typical clinical signs and lesions, a history consistent with vector transmission and confirmation by laboratory detection of virus and/or anti-AHS virus antibodies. The clinicopathologic presentation of AHS, current and next generation laboratory diagnostic methods are discussed.     

Role of paired basic residues in the expression of active recombinant galactosyltransferases from the bacterial pathogen Neisseria meningitidis

The lgtB gene encoding a beta-1,4-galactosyltransferase gene and the lgtC gene encoding an alpha-1,4-galactosyltransferase from the bacterial pathogen Neisseria meningitidis were cloned into an expression vector and overexpressed in Escherichia coli. Both genes expressed very well, but problems with C-terminal proteolysis were encountered with both proteins. The lgtC protein was initially isolated from extracts of recombinant E.coli as a truncated species that retained enzymatic activity, and was subsequently shown by mass spectrometry to be 19 residues shorter than the expected protein. A specific set of engineered C-terminal deletions was constructed to investigate their effect on the expression of lgtC. As many as 28 residues could be deleted with little effect on activity, and with the concomitant improvement of the overall expression up to fivefold over the full length protein. The lgtB protein was also proteolysed in extracts of normal E.coli strains into enzymatically inactive fragments lacking 28 or 41 C-terminal residues. This degradation could be prevented by expression in an ompT protease deficient strain of E.coli. The full length lgtB protein was not stable in soluble protein extracts from all recombinant strains, however a stable enzyme preparation could be achieved with the membrane fraction from cells of the ompT deficient strain expressing lgtB. Specific deletions of lgtB were also constructed, and 15 residues could be removed without loss of enzyme activity and also with the concomitant improvement of the overall expression up to twofold over the full length protein. Longer deletions produced protein but activity could not be detected in these recombinant strains. Examination of the glycosyltransferase sequences from a wide range of bacteria showed their C-terminal segments of approximately 50 amino acids frequently contained paired basic residues. Engineering of these segments may therefore be required as a general practice to produce these enzymes for use in the large scale chemi-enzymatic synthesis of carbohydrate-based therapeutics.      

Recombinant adeno-associated virus targets passenger gene expression to cones in primate retina

Recombinant adeno-associated virus (rAAV) is a promising vector for gene therapy of photoreceptor-based diseases. Previous studies have demonstrated that rAAV serotypes 2 and 5 can transduce both rod and cone photoreceptors in rodents and dogs, and it can target rods, but not cones in primates. Here we report that using a human cone-specific enhancer and promoter to regulate expression of a green fluorescent protein (GFP) reporter gene in an rAAV-5 vector successfully targeted expression of the reporter gene to primate cones, and the time course of GFP expression was able to be monitored in a living animal using the RetCam II digital imaging system.