A challenging case of severe bilateral septic arthritis with osteomyelitis of the sternoclavicular joint in a patient with end-stage renal disease

Septic arthritis of the sternoclavicular joint (SCJ) is a rare condition that comprises <1% of all joint infections. We report a case of severe bilateral septic arthritis of the SCJ in a patient with end-stage renal disease on peritoneal dialysis. A 44-year-old female presented with right SCJ infection 1 month after recovering from a tenckhoff catheter exit-site infection. She completed 6 weeks of antibiotics however this progressed to bilateral SCJ septic arthritis with osteomyelitis necessitating multiple surgical debridement and excision of bilateral clavicular heads. Further imaging showed signs of renal osteodystrophy and degenerative joint changes resembling calcium pyrophosphate deposition. Patients with end-stage renal disease have multiple risk factors including immune system dysfunction, renal osteodystrophy and dialysis access sites that increase susceptibility to bacteraemia and seeding. Therefore in such patients, prompt assessment is necessary to ensure expeditious diagnosis and treatment of this potentially debilitating condition. A multidisciplinary team involving various specialties is crucial for the holistic care for such patients and to reduce the risk of recurrence.

Systematic review of the efficacy of a hybrid operating theatre in the management of severe trauma

Background

Hybrid operating theatres (OT) allow for simultaneous interventional radiology and operative procedures, serving as a one-stop facility for the treatment of severely injured patients. Several countries have adopted the use of the hybrid OT however their clinical impact in improving efficiency and quality of care remains unclear. This study systematically reviews the clinical impact of the hybrid OT for treatment of the severely injured.

Methods

A literature review of the PubMed, Embase and Cochrane databases was performed to identify all published articles in English, from 1st January 2000 to 31st December 2020, reporting on the impact of a hybrid OT for severe trauma. Articles were also reviewed for references of interest.

Results

Five studies reporting the clinical impact of the hybrid OT, in a total of 951 patients, were shortlisted. All were cohort studies that compared patient outcomes in the hybrid OT versus a conventional group. Out of 3 studies that assessed timeliness to intervention, one reported shorter time associated with the hybrid OT, while the other two reported no difference. Mortality outcomes were reported in 4 studies and showed no significant difference associated with treatment in the hybrid OT. Two studies revealed shorter total procedure times associated with the hybrid OT. Two out of 3 studies that evaluated blood transfusion requirements reported decreased transfusion rates in the hybrid OT group. Only 1 study examined complication rates and demonstrated morbidity benefits associated with the hybrid OT.

Conclusion

Establishment of a hybrid OT requires a significant capital investment as well as a highly functioning multi-disciplinary team. The cost–benefit ratio remains unclear. Future studies, preferably in the form of clinical trials, are required to evaluate its usefulness in improving timeliness to definitive haemorrhage control and outcomes in severe trauma.

Laparoscopic wedge resection for suspected large (≥5 cm) gastric gastrointestinal stromal tumors

BACKGROUND

Laparoscopic wedge resection (LWR) for small gastric gastrointestinal stromal tumors (GIST) is now widely accepted, but its application for large GISTs remains controversial. This study aims to evaluate the feasibility and safety of LWR for suspected large (≥5 cm) gastric GISTs.

METHODS

Retrospective review of 82 consecutive patients who underwent attempted LWR for suspected gastric GIST. LWR for large (≥5 cm) (n = 23) tumors was compared with LWR for small (<5 cm) tumors (n = 59). The 23 patients with LWR for large tumors were also compared to 36 consecutive patients who underwent open wedge resection (OWR) for large tumors.

RESULTS

Comparison between patients who underwent LWR for large versus small tumors demonstrated that resection of large tumors was associated with a longer operating time. There was no difference in other perioperative outcomes, and oncological outcomes such as frequency of close margins (≤1 mm) and recurrence-free survival. Comparison between patients who underwent LWR versus OWR for large tumors showed that LWR was associated with decreased median time to fluid or solid diet, shorter postoperative stay but longer operating times. There was no difference in oncological outcomes.

CONCLUSION

LWR for suspected large gastric GIST is feasible and safe. It is associated with similar short-term outcomes with LWR for small tumors and favorable short-term outcomes over OWR for large tumors without compromising on oncological outcomes.

A 3-year study on the effect of RGP contact lenses on myopic children

AIM AND BACKGROUND

Recent studies in the West have shown that rigid gas-permeable (RGP) contact lenses can control the progress of myopia in children. These studies were done on Caucasian children, whose myopias are less rapidly progressive than those which we see in Singaporean children. This three-year study was started in 1993, with the following objectives: 1. To verify whether RGP contact lenses can control the progress of myopia in Singaporean children. 2. If so, to investigate the mechanism by which the lenses control myopia; whether by corneal flattening or by reducing the growth of the axial length. 3. If so, to assess if the effects are permanent, by discontinuing lens wear.

MATERIALS AND METHODS

The study was carried out at the Eye Clinic of the School Health Service. Enough school children were referred to the clinic from the various schools to achieve about 100 children wearing contact lenses. Past studies showed that the drop-out rate would be 50%, as there is no cosmetic motivation in 10 year-old children to wear contact lenses. The successful wearers were those who had parental encouragement and support.

RESULTS

The results show that there was a suppression of the progress of myopia in children wearing the lenses as compared to their counterparts wearing spectacles. However, only in ten eyes was there arrest of the myopia. For the lenses to be effective, they needed to be worn regularly for about eight hours a day. Reasons for the drop-outs included lack of motivation, lens intolerance and simply being too busy with the school curriculum. Discontinuance of lens wear for more than 2 months had minimal effect on the refraction, indicating that the controlling effect was not due purely to corneal change.

CONCLUSION

It is recommended that more studies be done to confirm the findings of this study. Children with rapidly progressive myopia can wear rigid gas-permeable contact lenses to reduce the progression.

The nuclear envelope prevents reinitiation of replication by regulating the binding of MCM3 to chromatin in Xenopus egg extracts

BACKGROUND

A complex of MCM proteins is implicated in ensuring that DNA replicates only once in each cell cycle, by 'replication licensing'. The nuclear membrane is also implicated in replication licensing, but the relationship between the MCM proteins and the nuclear membrane is unclear. Here, we investigate the relationship between XMCM3 (a component of the Xenopus MCM complex), nuclear envelope permeability and the initiation of DNA replication once per cell cycle.

RESULTS

Our results show that the nuclear envelope does not prevent the entry of XMCM3 into the nucleus, but that it does prevent the binding of XMCM3 to chromatin. We have also identified another component of the Xenopus MCM complex as a homologue of the Schizosaccharomyces pombe protein Cdc21. XMCM3 does not preferentially co-localize with sites of DNA replication. Instead, it is almost uniformly distributed on chromatin and is suddenly lost during replication. XMCM3 crosses intact nuclear membranes of G2-phase HeLa cells but cannot then bind to chromatin. Permeabilization of the nuclear envelope allows the binding of XMCM3 to G2-phase chromatin. We have therefore resolved replication licensing into two stages. The first requires the entry of a cytosolic 'loading factor' that is excluded by the nuclear membrane; subsequently, MCM3 can bind to chromatin in the presence or absence of a nuclear membrane, but only if the loading factor has gained access in the absence of the membrane.

CONCLUSIONS

The Xenopus MCM complex contains homologues of yeast MCM2, MCM3, MCM5 and Cdc21 proteins. XMCM3 is displaced from chromatin during replication. The nuclear envelope allows entry of XMCM3 into the nucleus, but regulates its binding to chromatin; binding requires a loading factor which cannot cross the nuclear envelope. Based on these results we present a two-stage model for replication licensing.

Purification of an MCM-containing complex as a component of the DNA replication licensing system

Replication licensing factor (RLF) ensures that eukaryotic chromosomal DNA is replicated exactly once in each cell cycle. On exit from metaphase, RLF is activated and binds to or modifies chromatin. This modification (the 'licence') is required for subsequent DNA replication; the licence is also inactivated in the process of replication. Active RLF is not imported into the nucleus, so further DNA replication cannot occur until the DNA is relicensed by passage throught mitosis. We have developed an assay to purify RLF from Xenopus eggs. Activity resolves into two components, RLF-M and RLF-B, both of which are required for licensing. RLF-M has been purified to apparent homogeneity: it consists of three polypeptides, one of which is a Xenopus homologue of the yeast MCM3 protein. Xenopus Mcm3 associates with chomatin in G1 and is removed during replication, consistent with its being a component of the RLF system.

MCM3 complex required for cell cycle regulation of DNA replication in vertebrate cells

An intact nuclear membrane restricts DNA replication to only one round in each cell cycle, apparently by excluding an essential replication-licensing factor throughout interphase. A family of related yeast replication proteins, MCM2, 3 and 5 (also called, after cell-division cycle, CDC46), resemble licensing factor, entering the nucleus only during mitosis. We have cloned a Xenopus homologue of MCM3 (XMCM3) and raised antibodies against expressed protein. Immunodepletion of Xenopus egg extracts removes a complex of MCM2, 3 and 5 homologues and inhibits replication of Xenopus sperm nuclei or permeable G2 HeLa nuclei. However, G1 HeLa nuclei still replicate efficiently. Mock-depleted extracts replicate all three templates. XMCM3 accumulates in nuclei before replication but anti-XMCM3 staining decreases during replication. These results can explain why replicated nuclei are unable to reinitiate replication in a single cell cycle.

Can contact lenses control the progression of myopia?

Myopia is a potentially blinding condition with serious socio-economic ramifications. Many causes have been alluded to and one of the strongest associations is that of formal education and nearwork. Studies done both locally and abroad illustrate this. In addition, Singaporeans were found to have one of the highest incidences of myopia in the world. Many methods, including the use of contact lenses, have been advocated in the control of myopia. Hard contact lenses and more recently, rigid gas permeable lenses, have been studied both to arrest the progression of myopia in the young and reduce existing myopia (by orthokeratology) in the Caucasian population. However, the Asian eye differs from the Caucasian eye. This is evidenced by the increased frequency and severity of myopia, and the difference in the pattern of corneal diseases in our population. As such, there is a need for local studies to be conducted to assess the effectiveness of this method in our population.

Spontaneous hematic cysts of the orbit presenting with acute proptosis. A report of three cases

Three cases of spontaneous hematic cyst of the orbit are described. All cases presented with acute onset of proptosis, conjunctival chemosis, choroidal folds, restricted ocular movement, and optic nerve compression syndrome with very poor vision. A computed tomography scan demonstrated a cystic lesion situated in the upper part of the orbit. Exploration revealed a cyst containing chocolate-colored fluid. Visual recovery was complete in two of three cases. There was no definite history of trauma in all three cases. Chronic hematic cysts have been described recently, but cases with acute onset such as ours have not to our knowledge been described clearly.

Local anaesthesia without retrobulbar injection

Images

Corneal blindness in Singapore and its prevention

The pattern of corneal disorders in Singapore is different from that seen in the western countries, and in the developing countries. Dendritic corneal ulceration, keratoconus and corneal dystrophy are relatively uncommon. Bullous Keratopathy, however, is on the increase, due mainly to the increasing number of cataract operations done and to the use of intraocular implants. Other major corneal disorders in Singapore are Exposure Keratitis and Neurotrophic Keratitis. The management of the various corneal disorders are discussed. Prevention is possible especially in those disorders due to iatrogenic factors. Constant vigilance and care are called for to prevent unnecessary surgical trauma and corneal blindness.

Eye diseases in the elderly in Singapore

Ocular disorders in the elderly have become more important because of increased longevity and the demand for good vision. Many serious ocular conditions are age-related and they include cataract, glaucoma, diabetic retinopathy and other retinal conditions. The most important ocular disorder is cataract which fortunately is curable with excellent results when a posterior chamber implant is inserted. Angle closure glaucoma is common in the elderly Singapore Chinese and can be effectively treated with microscopic peripheral iridectomy or trabeculectomy. Blindness from diabetic retinopathy can be prevented with argon laser photocoagulation. In most cases blindness is preventable with early diagnosis e.g. in glaucoma and diabetic retinopathy. Severe visual loss in the elderly requires careful explanation and compassion by doctors and social workers.

Argon laser photocoagulation in diabetic retinopathy: five year review of 697 treated eyes

Diabetic retinopathy has now become a common cause of blindness in Singapore. Fortunately, laser photocoagulation has prevented blindness in the majority of patients who were treated. An analysis of 872 patients treated with argon laser photocoagulation showed that 424 patients (48.6%) were for diabetic retinopathy. Patients with adequate treatment retained useful vision. Those who lost vision frequently had associated target organ involvement besides inadequate laser treatment. Patients with proliferative diabetic retinopathy were treated with peripheral retinal photocoagulation. Patients with diabetic maculopathy especially those with focal leaks were treated with localised photocoagulation. A common cause of blindness is failure to recognise the condition early. Physicians and general practitioners must, in the management of diabetics, examine their patients periodically with the pupils dilated in a darkened room.