The amyloid precursor protein is not enriched in caveolae-like, detergent-insoluble membrane microdomains

The amyloid precursor protein may be processed by several different pathways, one of which produces the amyloid beta-peptide betaA4 present in the amyloid plaques characteristic of Alzheimer's disease. A recent report suggested that axonal-amyloid precursor protein is present in a membrane fraction "with caveolae-like properties." In the present study we have isolated detergent-insoluble, caveolae-like membranes from both mouse cerebellum and the human neuroblastoma cell line SH-SY5Y. Detergent-insoluble membranes from mouse cerebellum retained nearly all of the glycosylphosphatidylinositol-anchored proteins--alkaline phosphatase, 5'-nucleotidase, and the F3 protein--while excluding the majority of the plasmalemmal marker protein alkaline phosphodiesterase I. Although the inositol trisphosphate receptor was highly enriched in this detergent-insoluble fraction, neither amyloid precursor protein nor clathrin immunoreactivity could be detected. Similar results were obtained with SH-SY5Y cells, where 5'-nucleotidase activity was enriched at least 30-fold in the detergent-insoluble membranes, but no amyloid precursor protein or clathrin immunoreactivity could be detected. Caveolin could not be detected in microsomal membranes from either mouse cerebellum or SH-SY5Y cells. These observations suggest that amyloid precursor protein is not normally present in detergent-insoluble, caveolae-like membrane microdomains.

A bond percolation-based model for image segmentation

This work presents a novel bond percolation-based approach to determine the clique potential parameters of a Gibbs-Markov model as a function of local characteristics of the underlying image. Using the renormalization group transformation, a multiscale description of the clique potential parameters is formed and used to obtain multiresolution image segmentation.

A randomized double-blind comparative study of terbinafine for 1, 2 and 4 weeks in tinea capitis

We report a randomized, double-blind study, comparing the relative efficacy and tolerability of oral terbinafine, given for 1, 2 or 4 weeks, in tinea capitis. Of 161 evaluable patients, 53 were treated with terbinafine for 1 week, 51 for 2 weeks and 57 for 4 weeks. Isolated pathogens included Trichophyton violaceum (71.5%), T. tonsurans (14.9%), T. verrucosum (4.3%), Microsporum audouinii (4.3%), M. canis (2.5%), T. schoenleinii (1.9%) and T. mentagrophytes (0.6%). The final evaluation, at 12 weeks, showed cure rates of 73.6, 80.4 and 85.9%, in the respective groups. The adverse effects noted, were not drug related. In our opinion, terbinafine given for 1, 2 or 4 weeks, is equally effective for most cases of tinea capitis.

The association of hepatitis C viral infection with porphyria cutanea tarda in the Lothian region of Scotland

Porphyria cutanea tarda (PCT) is believed to be associated with reduced hepatic uroporphyrinogen decarboxylase activity and risk factors such as alcohol abuse and medication with oral contraceptives and certain other drugs. Recently it has been suggested that hepatitis C virus (HCV) infection may also be associated with PCT. We have therefore reviewed the prevalence of HCV infection in a series of patients with PCT in the Lothian region of Scotland. We identified 12 patients with PCT, all of whom had abnormal liver function tests. Liver histology revealed chronic active hepatitis in six patients, micronodular cirrhosis in four patients, hepatocellular carcinoma in one patient and normal findings in one HIV positive patient. Out of 12 patients tested, 11 were positive for anti-HCV antibodies by second generation enzyme linked immunosorbent assay (ELISA 2), and by recombinant immunoblot assay (RIBA 2); positive serology was confirmed by polymerase chain reaction (PCR). In a second group of 14 patients with chronic HCV infection matched for age and sex with the PCT patients, all had normal urinary uroporphyrin excretion. We have thus confirmed in Scotland early reports from Spain and Italy that PCT is strongly associated with HCV infection. This could explain the development of inflammatory changes in the liver and progression of liver disease in patients with PCT. Porphyrin metabolism, however, appears normal in patients with chronic HCV infection without PCT.

The effect of alcohol on acid secretion by the bovine gall bladder in vitro

OBJECTIVES

To determine whether acid secretion by gall bladder mucosa is influenced by alcohol and whether hydrogen ion output is increased when the gall bladder is perfused with moderate concentrations of alcohol.

METHODS

Fifty bovine gall bladders were studied. Twenty-five served as controls and 25 were perfused (in groups of five) with varying concentrations of alcohol (w/v): 0.05, 0.1, 0.2, 0.5 and 1.0%. Acid output was measured over 1 h and the results expressed as the mean.

RESULTS

There was no significant difference between acid production by control gall bladders and those perfused with 0.05% alcohol (24.30 +/- 8.7 versus 18.95 x 8.41 nmol/h), but the acid output was significantly increased when the mucosa was exposed to 0.1 and 0.2% alcohol concentrations (50.28 +/- 10.2 and 29.34 +/- 9.1 nmol/h; P < 0.001 and P < 0.0004, respectively). Perfusion with alcohol concentrations of 0.5 and 1.0%, significantly inhibited mucosal acid output (2.60 +/- 2.0 and -1.70 +/- 1.2 nmol/h; P < 0.0001 and P < 0.0001, respectively).

CONCLUSION

This study shows that perfusion of bovine gall bladder mucosa in vitro with moderate concentrations of alcohol stimulates acid output. This observation is important for assessing the link between alcohol and the risk of gallstone formation.

Use of a Heimlich flutter valve for pneumothorax in cystic fibrosis

The use of a Heimlich flutter valve in an adult patient with cystic fibrosis with hypercapnic respiratory failure which allowed resolution of a persisting pneumothorax after failure of conventional tube drainage is reported. The patient was managed at home and avoided surgical pleurodesis which could have jeopardised transplantation at a later date.

Adjuvanted subunit vaccines for the control of Salmonella enteritidis infection in turkeys

Liposomes and immunostimulating complexes (ISCOM) are adjuvants that have been known to potentiate the immune response to membrane proteins. Adjuvanted outer membrane proteins (OMP) from Salmonella enteritidis were evaluated for their protective efficacy against S enteritidis infection in turkeys. The adjuvanted vaccines prepared for evaluation were: positive or negatively charged liposomes, lipid-conjugated ISCOM, and mineral oil vaccines. These preparations were compared with that of a whole cell bacterin and protein alone. After vaccination, turkeys were challenge-exposed with a nalidixic acid-resistant strain of S enteritidis. They were monitored for clinical signs of disease, antibody response, bacterial shedding pattern, and clearance of the challenge S enteritidis from internal organs. Results indicated a significantly (P < 0.05) higher antibody response to the positively charged liposomal OMP vaccine, compared with the whole cell bacterin. The antibody response to positively charged liposomal OMP vaccine was greater when a booster dose of this preparation was given. Shedding of S enteritidis was decreased in all vaccinated and challenge-exposed turkeys (P < 0.001). The tissues from a high percentage (90 to 100%) of birds that received a booster vaccination of the liposomal (+ or -) and ISCOM vaccine were culture-negative for S enteritidis.

Tinea capitis in Lahore, Pakistan

BACKGROUND

The causative fungi of tinea capitis vary with geography and time. This study was planned to identify the etiologic agents and determine clinicoetiologic correlations of tinea capitis in Lahore, Pakistan.

METHODS

From clinically suspected cases of tinea capitis, skin scrapings and hair samples were taken and subjected to microscopy and culture.

RESULTS

Of 180 evaluable patients, 95% were children below 12 years of age with equal sex incidence. Noninflammatory lesions were seen in 62.2% of cases. Trichophyton violaceum was the most common etiologic agent responsible for 69.4% of infection, followed by T. tonsurans (16.7%), T. verrucosum (10%), Microsporum audouinii (2.2%), and T. mentagrophytes (1.7%).

CONCLUSIONS

T. violaceum is the predominant pathogen causing tinea capitis in children and adults in this part of the world and gives rise to a varied clinical picture. Our findings agree with data from other parts of Pakistan and many countries abroad.

Pathogenesis of hemorrhagic enteritis virus infection in turkeys

The pathogenesis of hemorrhagic enteritis was investigated in 4-week-old specific-pathogen-free (SPF) turkeys after oral administration of hemorrhagic enteritis virus. The virus antigen was detected and quantified in tissues at various days post-infection (DPI) by an avidin-biotin-enhanced enzyme immunoassay and was located by a monoclonal antibody-based immunoperoxidase (IP) staining technique. In the intestinal tract, low levels of viral antigen were detected from 1 to 3 and 9 to 15 DPI, whereas high antigen levels were found from 4 to 7 DPI. The bursa had viral antigen from 2 to 7 DPI. The plasma fraction of blood was positive for the antigen at day 1 PI and the cellular fraction of blood on day 3 PI. Antigen was first detected in the spleen at 2 DPI and reached a peak on day 6 PI. Initially, the viral antigen was present in a few reticular cells of the spleen and an increase in IP positive cells occurred with time. The maximum number of inclusion bodies in the spleen were found on day 6 PI. Following splenomegaly, viremia resulted in high levels of the virus appearing in the lamina propria of the small intestine. The lamina propria had numerous lymphoreticular cells positive for intranuclear viral inclusions from 5-7 DPI. It was at this time that intestinal congestion and hemorrhage were seen. The results suggest that HEV replicates first in the lymphoid cells of intestinal tract including the bursa, and then in those of the spleen with consequent HEV antigen widely distributed in the body. The time course of the high levels of HEV (mainly 4-7 DPI) in the lymphoid organs (cells), and occurrence of hemorrhagic enteritis (congestion, hyperemia) from 5 to 7 DPI and intestinal hemorrhage (5-8 DPI) appear to suggest that the intestinal lesion may be an immune-mediated response.

Canalicular infection caused by Actinomyces

We present 7 cases of canalicular involvement with Actinomyces collected over a 5-year period. All patients had involvement of one canaliculus, upper or lower, with lacrimal drainage patent to syringing. Curettings obtained by incising the involved canaliculi yielded Actinomyces species (5 cases) and Arachnia propionica (2 cases), typically in association with a mixed bacterial growth. Our results show that these patients often remain undiagnosed for months or even years, and are treated inappropriately for their recurrent symptoms. Despite sensitivity of Actinomyces to a broad spectrum of antibiotics, medical therapy alone does not eradicate the disease, and surgical evacuation of all concretions is essential to achieve a cure.

A monoclonal antibody-based immunoperoxidase method for rapid detection of haemorrhagic enteritis virus of turkeys

An indirect immunoperoxidase (IP) technique involving avidin-biotin peroxidase complex, using a monoclonal antibody was developed for the detection of haemorrhagic enteritis (HE) virus antigen in frozen and formalin-fixed paraffin-embedded tissue sections. This IP procedure was compared with an indirect immunofluorescence antibody technique (IFAT) and an agar gel precipitation test (AGPT). Spleens from turkeys experimentally infected with HE virus were collected and examined for the presence of viral antigen. The IP staining procedure detected HE viral antigen as early as 48 hours after infection and continued to demonstrate the presence of viral antigen for up to 11 days after infection at which time the experiment was terminated. The antigen was detected from three to seven days and from two to nine days after infection by the AGPT and IFAT, respectively. The IFAT and AGPT had sensitivities of 74.19 and 48 per cent, respectively, compared with IP. Because of its high sensitivity and specificity, the IP technique could be useful for studying the pathogenesis and rapid laboratory detection of HE virus.

Cardiopulmonary resuscitation skills of dental personnel

This study assessed the cardiopulmonary resuscitation (CPR) skills of 25 dental personnel. Theory was tested by multiple choice questionnaire (MCQ) and practical skills assessed using a recording Resusci-Anne manikin. The assessment was based upon the recommendations of the Resuscitation Council of the UK. Seven of the 16 dental students and six of the nine house officers tested passed the MCQ examination. All failed the practical assessment. It is concluded that more emphasis should be placed upon CPR instruction in undergraduate dental courses and that regular update courses are advisable to maintain CPR skill.

An open clinical pilot study of the efficacy and safety of oral terbinafine in dry non-inflammatory tinea capitis

Ten patients with dry non-inflammatory tinea capitis were evaluated in a pilot study which ran from September 1989 to February 1990. Each patient was given oral terbinafine for 6 weeks; each was followed up 2 weeks later. Eight (80%) were completely cured, one (10%) was mycologically cured and showed minimal signs and symptoms, and another (10%) showed improvement (negative mycology, but persistent clinical signs and symptoms). No topical or systemic side-effects were noted. Terbinafine appears to be an effective and safe antifungal agent in the treatment of non-inflammatory tinea capitis.