Sterile abscess mimicking recurrent tumour in the cerebellopontine angle

Vestibular schwannomas are the most common tumours encountered in the cerebellopontine angle (CPA) region, accounting for 90 per cent of all lesions. Early pyogenic abscess following surgery and delayed abscesses due to retained foreign bodies have been reported. We describe a case of sterile abscess of unknown aetiology in the CPA region, occurring 13 years after surgical excision of a vestibular schwannoma. The clinical and radiological features were suggestive of recurrent vestibular schwannoma or malignant transformation. We believe this is the first reported case of delayed occurrence of sterile abscess in the CPA region. Further the diagnostic difficulties of such rare lesions occurring in the CPA after vestibular schwannoma surgery are discussed.

Growth of AM fungi on in vitro root organ culture of Sorghum vulgare and Saccharum officinarum

Spores of Gl mosseae and Gig gigantea germinated on minimal medium produced extraradical mycelium. Gl. mosseae infected roots of S. officinarum in in vitro condition were inoculated in M medium with in vitro cultured roots of Sorghum vulgare (test roots). From the infected root of S. officinarum, the mycelium developed and it infected the test roots. The roots developed new mycelia and further the mycelia produced a few hyaline spores. In MS medium combined with soil extract, root exudate, thiamine HCl and inositol combination, spore germination and germ tube growth were higher when compared with other media.

A study in two centres of variations in the time of apical barrier detection and barrier position in nonvital immature permanent incisors

OBJECTIVES

To study barrier formation in nonvital, immature permanent incisors being treated using the apexification technique in two centres, and to establish the effect of the frequency of change of calcium hydroxide (CaOH) on barrier detection times.

DESIGN

A retrospective study of the time of detection and the position of barriers.

RESULTS

There were no significant differences between the two centres in terms of the average frequency of change of each CaOH dressing, the distribution of barrier detection times or the position of barriers (P > 0.05). There was a total of 107 teeth and the time of barrier detection was significantly earlier in more frequently dressed teeth (P = 0.013). Of the teeth with a barrier detection time of less than 9 months, 60.7% were dressed more frequently than every 3 months, as opposed to 39.1% of teeth with longer barrier times (P = 0.027). The mean time of barrier detection for all cases was 43.3 weeks. The majority of barriers were located at or near the apex.

CONCLUSION

The frequency of change of CaOH can increase the speed of barrier detection but does not appear to affect the position.

Dynamic simulation of the laboratory-scale controlled ecological life support system

There are a number of design and control issues that need to be resolved in order to make a crop growth chamber an integral part of a controlled ecological life support system (CELSS) capable of supporting life on extended space missions. A modeling and simulation effort, along with the construction of an experimental testbed, are underway at NASA Ames Research Center to explore the long-term dynamic behavior of closed-loop life support systems. One problem that has been isolated for investigation is the stability and robustness of closed-loop systems over extended periods of time. Currently a crop growth chamber is being integrated with a solid waste processor to study closure of the carbon loop. A dynamic simulation model of the system was developed to evaluate system design options and operational alternatives. The model was also used to simulate the impact of system buffer size on the dynamic behavior of conditions inside the crop growth chamber.

Renal artery embolization for benign obstructive uropathy

PURPOSE

We demonstrate safety of renal artery embolization as an alternative to nephrectomy in symptomatic patients with obstructed, poorly functioning kidneys who are unfit for surgery.

MATERIALS AND METHODS

We performed renal artery embolization in 2 medically unfit patients with benign obstructive uropathy and poorly functioning kidneys. The affected kidney was initially drained with a nephrostomy tube and the kidney was then selectively embolized using absorbable gelatin sponge particles and Gianturco coils. The nephrostomy tube was removed before hospital discharge.

RESULTS

Urine production by the affected kidney ceased and symptoms resolved.

CONCLUSIONS

Renal artery embolization with antegrade drainage is a safe alternative to surgery in unfit symptomatic patients with benign obstructive uropathy and poorly functioning kidneys.

Beneficial role of amino acids in mitigating cytoskeletal actin glycation and improving F-actin content: in vitro

AIMS

The actin filaments present in circulating leukocytes facilitate their passage through microvenules and capillaries by helping in their deformability. Decreased deformability of granulocytes is now known to cause occlusion of the retinal microcapillaries leading to hypoxia and the subsequent development of diabetic retinopathy. Structural and functional loss of proteins, due to non-enzymatic glycation and glycoxidation, has been reported to cause diabetic pathogenesis. As amino acids have been earlier reported to have antidiabetic properties, the present study involves the investigation of the susceptibility of the cytoskeletal actin to glycation and its mitigation by free amino acids. This study also involves quantifying F-actin in cultured mononuclear cells obtained from diabetic and normal healthy volunteers and on the effect of glucose and free amino acids on F-actin content.

METHODS

Commercial non-muscle actin and actin immuno-pre-cipitated from granulocytes obtained from (a) normal healthy human volunteers and (b) patients with type 2 diabetes mellitus were subjected to glycation studies using [U] (14)C glucose. The effect of free amino acids, as antiglycating agents, was determined using various concentrations of lysine, arginine, alanine, aspartic acid and glutamic acid. F-actin content in cultured mononuclear cells was estimated by flow cytometry using fluorescein isothiocynate (FITC)-Phalloidin.

RESULTS

Commercial actin at physiological conditions of pH and temperature was found to undergo non-enzymatic glycation. The extent of in vitro glycation was significantly low (P<0.001) in actin isolated from patients with type2 diabetes when compared to the non-diabetic group, suggesting an increased in vitro structural modification of actin in patients with diabetes. All the free amino acids tested were found to have varying degrees of antiglycating effect. The F-actin content in the intact mononuclear cells obtained from diabetic patients was found to be low when compared with normal healthy volunteers (P<0.001). Similarly the F-actin content was significantly low when the normal mononuclear cells were incubated with glucose. This effect was reversed upon the addition of free amino acids to the incubation mixture.

CONCLUSIONS

Free amino acids can play a positive role in improving leukocyte deformability by mitigating cytoskeletal actin glycation and improving F-actin content.

Fowlpox virus encodes a novel DNA repair enzyme, CPD-photolyase, that restores infectivity of UV light-damaged virus

Fowlpox virus (FPV), a pathogen of poultry, can persist in desiccated scabs shed from infected hosts. Although the mechanisms which ensure virus survival are unknown, it is likely that some type of remedial action against environmentally induced damage is required. In this regard, we have identified an open reading frame (ORF) coding for a putative class II cyclobutane pyrimidine dimer (CPD)-photolyase in the genome of FPV. This enzyme repairs the UV light-induced formation of CPDs in DNA by using blue light as an energy source and thus could enhance the viability of FPV during its exposure to sunlight. Based on transcriptional analyses, the photolyase gene was found to be expressed late during the FPV replicative cycle. That the resultant protein retained DNA repair activity was demonstrated by the ability of the corresponding FPV ORF to complement functionally a photolyase-deficient Escherichia coli strain. Interestingly, insertional inactivation of the FPV photolyase gene did not impair the replication of such a genetically altered virus in cultured cells. However, greater sensitivity of this mutant than of the parental virus to UV light irradiation was evident when both were subsequently photoreactivated in the absence of host participation. Therefore, FPV appears to incorporate its photolyase into mature virions where the enzyme can promote their survival in the environment. Although expression of a homologous protein has been predicted for some chordopoxviruses, this report is the first to demonstrate that a poxvirus can utilize light to repair damage to its genome.

Surgical management of intractable epistaxis: audit of results

We have audited our results after changing the management practice in patients with intractable epistaxis. These patients are offered trans-nasal endoscopic sphenopalatine artery diathermy with or without anterior ethmoid artery diathermy instead of conventional surgical procedures. During the first year after the change in practice, 145 patients were treated as inpatients for epistaxis. Ten patients (seven per cent) required a surgical procedure under general anaesthesia due to the recurrent nature of bleeding. All 10 patients had endoscopic sphenopalatine artery diathermy, whereas in four patients anterior ethmoid artery diathermy was also performed concurrently. The post-operative hospital stay ranged from one to three days (mean 2.1 days). The mean follow-up was 10 months. The epistaxis recurred in one patient and this was managed conservatively. There were no complications related to surgery. In the previous year, 132 patients were admitted for epistaxis and eight patients had surgical procedures, which included septoplasty, nasal packing and external carotid artery ligation. The post-operative stay ranged from three to six days (mean 3.9 days). Our audit shows that endoscopic sphenopalatine artery diathermy is a safe, successful and effective management option for patients with refractory epistaxis. The morbidity is reduced and the hospital stay is shortened. The sphenopalatine artery diathermy can be combined with anterior ethmoid surgery, when necessary.

Intraluminal pulmonary artery fibroma in a 7-year-old boy

A supravalvar intraluminal pulmonary artery fibroma, presenting as pulmonary stenosis, is described. This is a previously unreported location for this type of tumor.

Pars tensa retraction pockets in children: treatment by excision and ventilation tube insertion

Tympanic membrane retraction pockets involving the pars tensa are not uncommon in clinical practice. Recurrent infections, ossicular erosion and cholesteatoma are the recognized sequelae. The management options include surveillance, medical treatment and surgery. The surgical procedures range from grommet insertion to extensive tympanoplasty procedures. We report our experience with simple excision and grommet insertion, performed in 31 ears in 26 patients as day cases. The follow-up ranged from 8 to 34 months with a mean of 16 months. The procedure was successful in 23 ears (success rate of 74%). Recurrence of retraction occurred in seven ears and in one ear there was a persistent perforation. Age, previous grommet insertion and severity of retraction did not have a statistically significant influence on the final outcome. We conclude that excision and grommet insertion is a simple, safe and efficient procedure for the management of tympanic membrane retraction pockets and can be considered in preference to extensive tympanoplasty.

Packet classification using tuple space search

Routers must perform packet classification at high speeds to efficiently implement functions such as firewalls and QoS routing. Packet classification requires matching each packet against a database of filters (or rules), and forwarding the packet according to the highest priority filter. Existing filter schemes with fast lookup time do not scale to large filter databases. Other more scalable schemes work for 2-dimensional filters, but their lookup times degrade quickly with each additional dimension. While there exist good hardware solutions, our new schemes are geared towards software implementation.We introduce a generic packet classification algorithm, called Tuple Space Search (TSS) . Because real databases typically use only a small number of distinct field lengths, by mapping filters to tuples even a simple linear search of the tuple space can provide significant speedup over naive linear search over the filters. Each tuple is maintained as a hash table that can be searched in one memory access. We then introduce techniques for further refining the search of the tuple space, and demonstrate their effectiveness on some firewall databases. For example, a real database of 278 filters had a tuple space of 41 which our algorithm prunes to 11 tuples. Even as we increased the filter database size from 1K to 100K (using a random two-dimensional filter generation model), the number of tuples grew from 53 to only 186, and the pruned tuples only grew from 1 to 4. Our Pruned Tuple Space search is also the only scheme known to us that allows fast updates and fast search times. We also show a lower bound on the general tuple space search problem, and describe an optimal algorithm, called Rectangle Search , for two-dimensional filters.

Sphenoid sinus schwannoma treated by endoscopic excision

Schwannomas, arising from the Schwann cells of the nerve sheath, occur very rarely in the sino-nasal tract and histological diagnosis can, sometimes, be difficult. We describe a case of schwannoma of the sphenoidal sinus occurring in a 71-year-old man, who underwent complete excision of the tumour endoscopically. To our knowledge, this is the third case of sphenoid sinus schwannoma reported in the English literature.