The role of clonal haematopoiesis in cardiovascular diseases: epidemiology and experimental studies.

Clonal haematopoiesis results from acquired mutations in haematopoietic stem and progenitor cells (HSPCs). These mutations can confer the HSPC with a competitive advantage, leading to their clonal expansion within the limiting bone marrow niche. This process is often insufficient to produce a haematologic malignancy; however, the expanding HSPC clones increasingly give rise to progeny leucocytes whose phenotypes can be altered by the somatic mutations that they harbour. Key findings from multiple human studies have shown that clonal haematopoiesis in the absence of overt haematologic alterations is common amongst the ageing population and associated with mortality and cardiovascular disease. Key findings from experimental studies have provided evidence for a causative role for clonal haematopoiesis in cardiovascular diseases, and aspects of these mechanisms have been elucidated. Whilst our understanding of the impact and biology of clonal haematopoiesis is in its infancy, analyses of some of the most commonly mutated driver genes suggest promising clinical scenarios involving the development of personalized therapies with immunomodulatory drugs that exploit the perturbation caused by the particular mutation. Herein, we review the accumulating epidemiological and experimental evidence, and summarize our current understanding of the importance of clonal haematopoiesis as a new causal risk factor for atherosclerotic cardiovascular disease and heart failure.

Prevalence and genotypic relatedness of methicillin resistant Staphylococcus aureus in a tertiary care hospital.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is the most common multidrug-resistant pathogen causing nosocomial infections across the world. MRSA is not only associated with significant mortality and morbidity but also places a large economic strain on our health care system. MRSA isolates are also typically resistant to multiple, non-ß-lactam antibiotics. We conducted a prospective study in a tertiary care hospital, to determine the prevalence of MRSA and to establish the clonal distribution of MRSA isolates recovered from various clinical specimens. MATERIALS AND METHODS: Clinical samples were cultured and S. aureus was identified as per standard microbiological procedures. Susceptibility testing was done by agar disk diffusion and minimum inhibitory concentration (MIC) method as recommended by CLSI. Methicillin resistance was detected by phenotypic methods namely, oxacillin disc diffusion (ODD), minimum inhibitory concentration (MIC) of oxacillin, cefoxitin disk diffusion (CDD), and MIC of cefoxitin. Amplification of mecA gene by PCR was used as gold standard for detection of methicillin resistance. Pulsed field gel electrophoresis (PFGE) typing was performed for MRSA isolates. RESULTS: Out of 390 S. aureus isolates, 154 (39.48%) isolates were MRSA and 236 (60.51%) isolates were MSSA. Penicillin was the least effective antibacterial drug against the hospital associated S. aureus isolates with 85.64% resistance rate. All the isolates were susceptible to vancomycin. The MRSA showed a high level of resistance to all antimicrobials in general in comparison to the MSSA and the difference was statistically significant (P < 0.05). Multiplex PCR performed for all strains showed amplification of both the mecA and nucA genes in MRSA strains whereas MSSA strains showed amplification of only nucA gene. PFGE of these isolates showed 10 different patterns. CONCLUSION: Prevalence of MRSA in our hospital was 39.48%. Most of these isolates were resistant to erythromycin, clindamycin, cotrimoxazole, and ciprofloxacin, whereas high sensitivity was seen to vancomycin followed by gentamicin. CDD and MIC for cefoxitin showed 100% sensitivity, specificity, PPV and NPV as compared to PCR for mecA gene. In maximum number of isolates PFGE type A pattern was seen suggesting clonal relatedness.

An endophytic Neurospora sp. from Nothapodytes foetida producing camptothecin.

The medicinal plant, Nothapodytes foetida contains a number of important alkaloids like camptothecin (an anticancer drug molecule) but its concentration is less to meet the existing demand of this important molecule, so in an effort for accessible availability of camptothecin. An endophyte (designated ZP5SE) was isolated from the seed of Nothapodytes foetida and was examined as potential source of anticancer drug lead compound i.e. camptothecin, when grown in Sabouraud liquid culture media under shake flask conditions. The presence of anticancer compound (camptothecin) in this fungus was confirmed by chromatographic and spectroscopic methods in comparison with authentic camptothecin. Isolated endophyte (Neurospora crassa) producing camptothecin may become an easily accessible source for the production of precursor anticancer drug molecule in future at large scale.

Limb reconstruction by free-tissue transfer combined with the Ilizarov method.

In four complex cases of extremity reconstruction, we have been able to overcome the problems of combined bone and soft-tissue loss and length discrepancy by a combination of free-tissue transfer and the Ilizarov method of slow distraction. It is our observation that gradual distraction of a free tissue is a safe and viable procedure; the free tissue tolerates the pins of the circular external fixator well, and there is an equal degree of distraction and regeneration of the transferred free tissue and the native recipient tissue without evidence of wound dehiscence. Corticotomy through free tissue and in close proximity to vascularized bone is safe, with the subsequent bone regeneration not unlike that of normal bone. Manipulation by slow distraction does not appear to compromise the vasculature of the recipient bed for later microsurgical procedures or endanger the axial flow pattern of the transferred free tissue.

The floating radius in bipolar fracture-dislocation of the forearm.

Ten cases of bipolar forearm fracture-dislocation are presented. Recognition of the full extent of the skeletal, articular, and soft-tissue injuries is essential. Treatment consists of an anatomical reduction and proximal and distal stabilization of the skeleton to achieve control as well as maintain the position of the floating radius segment. The forearm bones can then be maintained in an optimal position to avoid interosseous soft-tissue contracture that will compromise the supination-pronation function of the forearm.

Customized staple fixation in hand and wrist surgery.

Fixation of small bones in the adult and the child's hands remains a challenge. The authors present a technique of bone fixation using customized staples made intraoperatively from K-wires (0.9-1.6 mm in diameter). Their specific purpose was to provide axial alignment and rotational stability for carpal bone fixation and for epiphysiodesis in phalanges. This technique was used in 14 cases (11 adult and three paediatric). No bone shattering, implant breakage, implant loosening or infection occurred. As K-wires are quite malleable, custom sized and shaped staples which follow the bone contours could be made to give a more exact fixation. All cases had satisfactory outcomes, achieving the preoperative objectives of bony fixation. This method is safe, precise and technically easy. It is also relatively cheap and only requires simple, standard instruments.

Free vascularised epiphyseal transplantation in upper extremity reconstruction.

We describe preliminary observations on the use of free vascularised transfer of proximal fibular epiphysis in replacement of proximal humeral epiphysis or distal radial epiphysis in three patients. An analysis of the early results shows evidence of longitudinal growth, graft hypertrophy and epiphyseal adaptation in transplanted epiphysis. A review of the problems in this type of surgery is included.

Combined free flap, Ilizarov lengthening and prosthetic fitting in the reconstruction of a proximal forearm amputation--a case report.

A composite free latissimus dorsi musculocutaneous flap combined with Ilizarov lengthening was used in the resurfacing of the elbow and the reconstruction of the forearm following a very proximal below elbow amputation with soft tissue degloving to the level of the mid arm. The free flap provided gliding soft tissue to the elbow joint, and the deep fascia and muscle components of the flap were contoured round the bony stump so as to allow bone transport within the soft tissue envelope. The lengthening achieved was 14 cm with no bone resorption at the end of the stump. The reconstructed forearm, with a well-contoured stump covered with durable and adherent soft tissue, allowed the fitting of a forearm-based lightweight hand glove prosthesis. With the combined modalities of microsurgical free tissue transfer, the Ilizarov method of slow distraction and prosthetic fitting, we were able to achieve restoration of both form and function in a difficult case of major upper extremity amputation.

A preliminary report of tissue preservation with University of Wisconsin cold storage solution in major limb replantation.

We report our results using University of Wisconsin (UW) cold storage solution in two cases of major replantation of the upper extremity. We employed a technique of a complete vascular washout with 1000 ml UW solution at 4 degrees Celsius at 120 cm hydrostatic pressure into the artery via a size 18 cannula. The ischaemic time of the amputated limbs were 7 hours and 11 1/4 hours respectively. No fasciotomy was performed upon revascularisation and minimal swelling was observed postoperatively. No post-ischaemic syndrome was encountered following the replantation surgery. With a follow-up of 10 and 16 months respectively, muscle and nerve viability were observed with sensory recovery and motor reinnervation. There was absence of muscle contracture and at subsequent surgical procedures, healthy musculature was present in the replanted limbs. These two clinical cases suggest that the UW solution has a role in extending the duration of tissue preservation and improving the quality of the tissues preserved.

Digital replantations under local anaesthesia.

We performed 10 digital replantations under local anaesthesia. Nine were single digit replantations and one case had a digital replantation together with another digit revascularisation. Criteria for patient selection for the local anaesthetic procedure included healthy young individuals, solitary hand injury, ability to understand the procedure and a stable emotional makeup. A combination of 10 ml of lidocaine 1% and 10 ml of bupivacaine 0.5% was used for volar metacarpal block and a dorsal ring block to the base of the digit. The patient was simultaneously sedated with 10 mg diazepam intramuscularly. Standard intraoperative monitoring of blood pressure, continuous electrocardiogram and pulse oximeter were carried out. The average duration of surgery was 3 hours. There was complete pain relief intraoperatively and good postoperative sensory block for an additional 7 to 15 hours. The technical execution of microsurgery was not compromised. All replantations were successful with no complication encountered from the use of local anaesthesia.

Extremity osteosarcoma--a Southeast Asian experience.

INTRODUCTION: We present our experience with limb salvage emphasising the use of vascularised bone grafts in combination with autoclaved tumour bone for limb salvage in osteosarcoma. MATERIALS AND METHODS: Thirty-six cases with extremity osteosarcoma, all of which were managed at a single institution between 1980 and 1999, were reviewed at a mean follow-up of 9 years (range, 10 months to 200 months). There were 26 patients who underwent limb salvage surgery and 10 patients who had amputation. RESULTS: In the limb salvage group, 12 bone defects were bridged using vascularised bone grafts alone while autoclaved tumour bone was used for reconstruction in the remaining 14 patients. In these 14, there were 10 with autoclaved tumour bone and vascularised bone, 2 with autoclaved bone and non-vascularised bone and 2 with autoclaved bone alone. The joint was preserved in 13 of the 26 reconstructions. Of these, 11 involved preservation of the knee joint contributing to a quantum gain in function with 84% good and excellent results. The actuarial survival was 64% at 2 years and 48% at 5 years, with no significant difference between ablation and limb salvage. CONCLUSION: The use of the autoclaved bone provided yet another effective alternative for bridging large defects following resection of high grade tumours.

Aesthetic life-like finger and hand prostheses: prosthetic prescription and factors influencing choices.

This paper reviews the authors' experience with fitting life-like finger and hand prosthesis. The methodology and technical considerations in producing these prostheses, the prosthetic prescription according to the level of amputation and the challenges faced with each level are discussed. In cases where the amputation is sufficiently distal, a thimble prosthesis has been used. This is compared to fitting a full-length finger prosthesis. Besides allowing free range of motion of the proximal finger joints which would otherwise be covered and restricted with fitting a finger prosthesis, a thimble prosthesis minimises skin coverage for optimal sensibility and is easier to don and doff. In cases of amputations where a digital fitting is precluded, a partial or a total hand is prescribed. A comparison between fitting a finger, a partial hand prosthesis and a total hand prosthesis is also discussed. Cases of a digital, transcarpal and a more proximal transmetacarpal amputations are relatively easy to fit with a prosthesis. An incomplete transmetacarpal amputation where much of the breadth of the hand is preserved presents a difficult challenge as it necessitates fitting with a partial hand prosthesis. Besides the need to cover a large area of the intact skin and the associated problems with reduced sensibility and stump perspiration, a partial hand prosthesis is difficult to don and doff.

Lengthening in free vascularized fibular graft.

A free vascularized fibular bone transfer was successfully performed in a 1-year-old child to reconstruct the loss of the right humeral shaft following neonatal osteomyelitis. Subsequent growth of the child resulted in gross arm length discrepancy, with associated functional deficits. Callostatic distraction-lengthening of the vascularized fibular graft was carried out to compensate for this limb length discrepancy by using an Ilizarov external fixator. Lengthening of 6 cm over a 3-month period, representing a 75% increase in the original length of the transplanted fibula, was achieved. Active bone regeneration, good corticalization and endosteal medullary cavity formation was observed in the lengthened fibula. The combined modalities of vascularized bone transfer and Ilizarov callostatic distraction-lengthening offer a solution for reconstruction for large segmental bone loss associated with growth arrest of the epiphyseal plates in children.

Lifelikeness in multilayered digital prostheses.

The appearance of the skin is dependent on the optical properties of the various layers of tissue and the presence of pigments. In order to reproduce the lifelikeness of the skin in developing digital prostheses, a multiple layered moulding technique was utilised. The prosthesis was moulded in two coloured layers, an outer layer and an inner layer. Four combinations of multiple coloured layers and two single coloured layers varying in their optical properties and base colours were assessed. In two groups an additional intermediate layer of detailed colours was added between the two layers, to enhance the creaselines, nails, blood vessels, and other features. All prosthesis were moulded to a total thickness of 0.6 mm. This method of moulding was based on the anatomical characteristics of the epidermal and dermal layers of the skin and their optical characteristics. The aim was to determine which combination of multiple layers gave the best outcome and made the prosthesis look lifelike in appearance. The appearance and lifelikeness of the prostheses were qualitatively assessed by a panel of assessers divided according to their vocation. The study showed that the best combination for moulding the prosthesis in multiple layers was to have the outer layer translucent and the inner layer opaque. An intermediate layer should be incorporated to enhance the more prominent surface features and the nails. The base colour of the inner layer should be darker than the outer layer to allow the intermediate layer to have a reflective background.

Fungal colonisation in digital silicone rubber prostheses.

The fungal discolouration of silicone rubber prostheses is reported in four cases. In two of the cases, the discolouration was caused by the fungus Candida tropicalis. In the other two cases, two different fungal organisms, namely Trichoderma sp. and Scedosporium prolificans were incriminated. The non-porous silicone rubber layers create an enclosed environment in the suction cup of the prosthesis and preclude ventilation at the prosthesis-stump interface. The moisture as a result of sweat and body warmth in the stump assists fungal growth. Residual salts from the sweat, sebum from sebaceous glands and the residues from petroleum jelly (Vaseline) applied to facilitate donning, can adhere to the surfaces of the prosthesis and provide the nutrients for fungal growth. Prolonged continuous usages of the prosthesis, the presence of sweaty palms in the users, donning the prosthesis during manual physical activities which induce perspiration, washing of hands with the prosthesis on and warm humid climatic conditions have been identified as factors predisposing the prosthesis to fungal colonisation. The fungal growth caused a black discolouration and marred the aesthetic quality of the prostheses. As a preventative measure, daily immersion of the prostheses in denture cleaner such as benzalkonium chloride, or water at 60 degrees C for 15 minutes, or decontamination with 70% alcohol is recommended. Prior cleaning to remove organic matter before decontamination is emphasised.

Metamerism in aesthetic prostheses under three standard illuminants--TL84, D65 and F.

This study looks at the effect of metamerism in colour-matching and the assessment of multi-layered silicone rubber finger prostheses. The aim was to identify the choice of illuminants for colour matching the prostheses that would give rise to the least metameric effect between the prostheses and the human skin or the best colour match. The prostheses were prepared and colour matched to a fair-skinned subject under 3 reference illuminants--TL84, D65, F and a combination of illuminants--TL84, D65 and F. The prostheses were then measured for colour using a spectrophotometer based on the CIE indices L*, a*, b* with each prosthesis assessed separately against the subject's index finger under the reference illuminants--TL84, D65 and F. The prostheses were also assessed by a panel of 50 observers and scored according to colour-match. Colour differences between the skin and prosthesis were measured in the illuminant under which the prostheses were prepared and then under the other reference illuminants. A relationship was obtained between the measured mean colour difference, deltaE*, and the mean visual assessment score for each prosthesis. This paper points out the concerns related to the optical phenomenon of metamerism with the colour pigments used. This can affect the colour match of the prosthesis as perceived by the patient. The findings seem to suggest that this metameric colour difference can be minimised if the prosthesis is matched under a combination of lights, which were found to give the best-perceived match.

Creating a model for fabricating a partial hand glove prosthesis using the realigned casts of the contralateral digits.

A method for creating a model for fabricating a partial hand glove prosthesis is described. The realigned casts of the corresponding digits of the contralateral uninjured hand were used to substitute for the lost digits on a cast of the stump. The technique allows an exact reproduction of the anatomical and fine surface details of the digits. It has the advantage of customisation, allowing a close match in the size, shape and surface characteristics of the prosthesis to that of the remaining digits of the hand.

Reconstruction of the humerus by soft tissue distraction and vascularized fibula transfer.

We report a case of reconstruction of the humeral shaft by soft tissue lengthening according to the method of Ilizarov, followed by skeletal reconstruction with a vascularized fibular graft. Skeletal union and initiation of functional activity were achieved within 4 months. Lengthening of the soft tissue and the vascular tree by slow distraction did not compromise the subsequent reconstructive microsurgical procedure.

A composite neuro-teno-cutaneous forearm flap in the one-stage reconstruction of a large defect of the soft tissue around the ankle.

The vascular anatomy of the radial forearm flap, incorporating the brachioradialis and palmaris tendons together with the superficial radial nerve in 20 fresh cadavers, is described. The radial artery in the cadaveric forearm was irrigated and injected with blue latex. The number and distribution of the cutaneous branches supplying the skin, brachioradialis tendon, palmaris tendon, and superficial radial nerve, were then documented in relation to the distance from the radiocarpal joint. The radial artery was found to provide adequate blood supply to the above structures. This flap has been used as a composite neuro-teno-cutaneous flap to resurface a large defect involving tendon, nerve, and skin loss in the ankle and the foot as a one-stage procedure. This technique avoids multiple-staged operations and thus shortens the convalescent period in rehabilitation of severely traumatized limbs.

Giant cell tumor of lumbar vertebra. A case report with 13-year followup.

A combined one stage anterior and posterior approach was used to excise a giant cell tumor involving the second lumbar vertebra. The tumor involved the anterior and posterior elements of the vertebra. A wide excision was feasible with immediate stabilization using the Luque instrumentation posteriorly and fibular strut grafts supporting the vertebral bodies anteriorly. The followup period was 13 years. There is no recurrence, and the patient has no symptoms of disease, and the fibular grafts are fully incorporated.