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R Nair

Publications and source records attributed to R Nair.

At least 37 records · Page 2Linked to original sources
PubMed2001

Obstructive sleep apnea is a false-negative cause of flow velocity paradoxus in pericardial effusion: case report.

We report on a patient with obstructive sleep apnea in whom percutaneous transmyocardial revascularization was complicated by hemopericardium. Absence of phasic variation in the transmitral and transtricuspid Doppler inflow velocities during apneic episodes and marked variation during spontaneous respiration were identified with a respirometer, and helped us identify a novel false-negative cause of flow velocity paradoxus.

Aged↗
PubMed2001

Spontaneous arteriovenous fistula resulting from HIV arteritis.

Arteriovenous fistulas (AVFs) are uncommon and usually follow trauma or preceding arterial catheterization or puncture. Spontaneous AVFs are rare. A case of spontaneous AVF of the superficial femoral artery and vein in an HIV-infected patient is presented. Histologic examination of the artery showed features similar to those seen in HIV-related large-vessel aneurysms. It would appear that spontaneous AVF are part of the spectrum of macrovascular arteritis related to HIV infection.

Adult↗
PubMed2001

Shark attack: review of 86 consecutive cases.

BACKGROUND: On average there are approximately 50 confirmed shark attacks worldwide annually. Despite their rarity, such incidents often generate much public and media attention. METHODS: The injuries of 86 consecutive victims of shark attack were reviewed from 1980 to 1999. Clinical data retrieved from the South African Shark Attack Files, maintained by the Natal Sharks Board, were retrospectively analyzed to determine the nature, treatment, and outcome of injuries. RESULTS: The majority of victims (n = 68 [81%]) had relatively minor injuries that required simple primary suture. Those patients (n = 16 [19%]) with more extensive limb lacerations longer than 20 cm or with soft-tissue loss of more than one myofascial compartment were associated with higher morbidity and limb loss. In 8 of the 10 fatalities, death occurred as a result of exsanguinating hemorrhage from a limb vascular injury. CONCLUSION: Victims of shark attack usually sustain only minor injuries. In more serious cases, particularly if associated with a major vascular injury, hemorrhage control and early resuscitation are of utmost importance during the initial management if these patients are to survive.

Adolescent↗
PubMed2001

Factitious hypoglycemia: a tale from the Arab world.

The mother is usually the one who narrates the patient's history to the pediatrician. Listening and eliciting the parent's story is an art. One of the essential attributes of a good pediatrician is the readiness to believe the parent's story. Mothers are good historians and careful observers. The axiom that the mother is always right is true in most instances. However, occasionally the clinician is deliberately misled by the storyteller, resulting in numerous and potentially dangerous diagnostic investigations. We describe a boy with recurrent hypoglycemic coma in whom the diagnosis of factitious hypoglycemia was delayed as it is believed to be nonexistent in our community. We emphasize that in all patients with recurrent hypoglycemia, estimation of C-peptide and insulin should be performed even when the clinical settings are not in favor of the diagnosis of Munchausen syndrome by proxy. Munchausen syndrome by proxy, hypoglycemia.

Child Abuse↗
PubMed2001

Hypothalamic digoxin mediated model for oncogenesis.

This study assessed the changes in the isoprenoid pathway and its metabolites digoxin, dolichol and ubiquinone in neoplasms (CNS astrocytomas - glioblastoma multiforme and high grade non - Hodgkin's lymphoma). The following parameters were assessed-isoprenoid pathway metabolites, tyrosine and tryptophan catabolites, glycoconjugate metabolism, RBC membrane composition and free radical metabolism. There was an elevation in plasma HMG CoA reductase activity, serum digoxin and dolichol and a reduction in RBC membrane Na+-K+ ATPase activity, serum ubiquinone and magnesium levels. Serum tryptophan, serotonin, nicotine and quinolinic acid were elevated while tyrosine, dopamine, noradrenaline and morphine were decreased. The total serum glycosaminoglycans and glycosaminoglycan fractions (except dermatan sulphate in the case of CNS astrocytomas), the activity of GAG degrading enzymes and glycohydrolases, carbohydrate residues of glycoproteins and serum glycolipids were elevated. HDL cholesterol showed a significant decrease and free fatty acids & triglycerides were increased. The RBC membrane glycosaminoglycans, hexose and fucose residues of glycoproteins and phospholipids were reduced. The activity of all free radical scavenging enzymes, concentration of glutathione, iron binding capacity and ceruloplasmin decreased significantly while the concentration of malondialdehyde (MDA), hydroperoxides, conjugated dienes and NO increased. The concentration of alpha tocopherol was unaltered. Membrane Na+-K+ ATPase inhibition due to elevated digoxin, altered membrane structure and digoxin related tyrosine / tryptophan transport defect leading to increased levels of depolarising tryptophan catabolites and decreased levels of hyperpolarising tyrosine catabolites can lead to alteration in intracellular calcium/magnesium ratios and oncogene activation. Intracellular magnesium deficiency can produce defective microtubule related spindle fibre dysfunction and chromosomal non-dysjunction contributing to neoplastic cellular polyploidy and aneuploidy. Digoxin induced tryptophan/tyrosine transport defect can alter neurotransmitter patterns with increased serotonin, quinolinic acid, nicotine & glutamatergic transmission and reduced dopamine, morphine and noradrenaline levels leading to oncogenesis. Glycoconjugate metabolism is altered by elevated dolichol levels and magnesium depletion consequent to Na+-K+ ATPase inhibition. There is a qualitative alteration in proteoglycans and glycoproteins, defective membrane formation and structure and reduced lysosomal stability leading to disordered contact inhibition and tumour antigen presentation contributing to oncogenesis. Digoxin induced alteration in intracellular calcium/magnesium ratios and low ubiquinone levels can lead to a mitochondrial dysfunction resulting in increased free radical generation and reduced scavenging & caspase-3 activation producing a P21 defect contributing to oncogenesis.

Adult↗
PubMed2001

Anastomotic aneurysm following aortobifemoral bypass.

OBJECTIVE: The aim of this study was to establish the incidence of anastomotic aneurysm following aortobifemoral bypass and to document management of this condition in our practice. DESIGN: This is a prospective study of anastomotic aneurysms developing in patients with aortobifemoral bypasses followed up for 49 months. SETTING: Two tertiary referral hospitals served by the Durban Metropolitan Vascular Service. PATIENTS: Four hundred and ninety-two patients underwent aortobifemoral bypass. Anastomotic aneurysms (N = 25) developed in 23 patients. Presence of anastomotic aneurysm was confirmed by Doppler ultrasound. INTERVENTIONS: All patients underwent aneurysm repair. RESULTS: Operations performed were: excision and interposition graft (15), re-suture (6), tube graft (1), crossover (1), graft-popliteal bypass (1) and ligation (1). There were no deaths and no recurrences. Wound infections occurred in 2 patients and occlusion of the opposite limb occurred in 1. CONCLUSION: Anastomotic aneurysms following aortobifemoral bypass are uncommon. They commonly occur as a result of anastomotic disruption. Management includes repair or excision, depending on the prevailing circumstances, and can be performed with good results.

Adult↗
PubMed2001

Comparison of external dacryocystorhinostomy and 5-fluorouracil augmented endonasal laser dacryocystorhinostomy. A retrospective review.

PURPOSE: To compare the success rates of external dacryocystorhinostomy (EXT-DCR) with 5-fluorouracil (5-FU) augmented endonasal laser dacryocystorhinostomy (ENL-DCR) and to record the complications associated with 5-FU augmented ENL-DCR MATERIALS AND METHODS: This was a retrospective non-randomised study. Forty-one patients with primary acquired nasolacrimal duct obstruction underwent an EXT-DCR (19 patients) or an ENL-DCR (22 patients) over a 3-year period. A Holmium YAG laser (Ho:YAG) was used in the latter group of patients. Silicone tubes intubated in all patients were removed at three months. 5-FU was applied intraoperatively at the site of the ostium in the ENL-DCR patients. The median follow-up was 12 months (range 3-24 months) for the ENL-DCR group and 22 months (range 6-28 months) for the EXT-DCR group. The patency of the lacrimal system and the severity of epiphora were assessed at a final-review. RESULTS: The median age of the EXT-DCR group was 77 years (range 53-87) and that of the ENL-DCR group was 71 years (range 23 to 84). There were 12 female patients in the former group and 19 in the latter. The percentage of success in the EXT-DCR group was 94.7% (95% confidence interval (CI) = 75.4-99.1) = ), and 63.6% in the ENL-DCR group (95% CI= 43.0-80.3). The confidence interval for the difference of 31.1% was 5.6-52.2. There was a statistically significant difference between the two groups, p=0.024 (Fisher exact test). CONCLUSIONS: These data suggest that EXT-DCR provides better results than 5-FU augmented ENL-DCR. However, ENL-DCR is the procedure of choice in certain circumstances such as in elderly, frail or medically unfit patients. Our results of 5-FU augmented ENL-DCR compare favourably with other published series.

Administration, Topical↗
PubMed2000

Fluorescence properties of rhodamine 800 in whole blood and plasma.

We have characterized the fluorescence spectral properties of rhodamine 800 (Rh800) in plasma and blood in order to test the possibility of making clinical fluorescence measurements in whole blood without separation steps. Rh800 was used because of its absorption at red/near-infrared wavelengths away from the absorption bands of hemoglobin. We utilized the front-face illumination and detection to minimize the effects of absorption and/or scatter during measurements. The presence of Rh800 was detected in plasma and blood using steady-state fluorescence measurements. Absorption due to hemoglobin reduced the Rh800 intensity from the blood. Fluorescence lifetime measurements in plasma and blood showed that it is possible to recover lifetime parameters of Rh800 in these media. We obtained mean lifetimes of 1.90 and 1.86 ns for Rh800 in plasma and blood, respectively. Using the recently described modulation sensing method, we quantified the concentrations of Rh800 in plasma and blood. Rh800 was detected at a concentration of as low as 2 microM in both media. High anisotropy values were obtained for Rh800 in plasma and blood using steady-state and anisotropy decay measurements, implying the tight binding of this probe to the contents of these media. This binding can be exploited to monitor the concentrations of different blood components using already existing or new red-emitting probes that will be specially designed to bind to these components with high specificity. To test this possibility of direct measurements in blood, we used Rh800 to monitor albumin in the presence of red blood cells. Increase in the polarization of Rh800 as the concentration of albumin was increased in the presence of the red cells showed the feasibility of such measurements.

Blood Chemical Analysis↗
PubMed2000

Large artery vasculopathy in HIV-positive patients: another vasculitic enigma.

Human immunodeficiency virus (HIV) infection has impacted on all the systems of the body, and the cardiovascular system is no exception, with small to medium-sized vessel vasculitis being most frequently described. We present 16 HIV-positive patients with large vessel disease consisting of either aneurysms (often multiple) or occlusive disease. Nine men and 7 women ranging in age from 18 to 38 years presented with rupture of aneurysm, transient ischemic attacks, hypertension, ischemia to the lower extremity, or a mass at the site of the aneurysm. Eight patients had 1 aneurysm, 2 had 2 lesions, and the remaining 6 cases had from 3 to 7 aneurysms. Arteries affected included the common carotid, abdominal aorta, common iliac, femoral, and popliteal. Three patients had intercurrent infections, but none had any obvious infective vascular lesion. Only 1 patient had a positive TPHA test for syphilis. Microbiologic culture of both blood and thrombus contents was positive for Staphylococcus aureus in 1 case; no other organisms were cultured. The key histological features were within the adventitia: leukocytoclastic vasculitis of the vasa vasora and periadventitial vessels, proliferation of slit-like vascular channels, chronic inflammation, and fibrosis. There was associated medial fibrosis with loss and fragmentation of muscle and elastic tissue. Intimal changes consisted of duplication and fragmentation of the internal elastic lamina with calcification. Atheroma and marked intimal thickening were not evident We believe that the occurrence of this large vessel vasculopathy (mainly aneurysmal) often with multiple lesions in young HIV-positive patients, is characteristic of possible infective or immune complex origin, with leukocytoclastic vasculitis of vasa vasora and periadventitial vessels being pivotal in many cases.

Adolescent↗
PubMed2000

Spontaneous carotid artery aneurysms.

BACKGROUND: Spontaneous carotid artery aneurysms are infrequently reported, and are almost always non-atherosclerotic. METHODS: The records of 29 patients with a spontaneous carotid aneurysm treated in an academic vascular unit between 1990 and 1998 were reviewed. RESULTS: All 29 patients were black South Africans; three had bilateral aneurysms. There were 24 men and five women, of mean age 35 (range 13-62) years. Some 25 aneurysms involved the common carotid artery, 12 of which affected the bifurcation, and seven were located in the internal carotid artery. Twenty-five aneurysms were managed surgically, four of which were ligated owing to sepsis. Histo- logical evaluation showed human immunodeficiency virus-related arteritis in four, tuberculous aneurysms in ten, Takayasu's arteritis in two, atherosclerosis in three and non-specific chronic inflammation in four patients. Microbiological examination was negative in all but one patient who had Salmonella sp. cultured. Outcome was generally favourable, but one patient died from massive hemispheric infarction. There were no other new neurological deficits. CONCLUSION: Carotid aneurysms pose a considerable surgical challenge but are amenable to operative intervention with good result. Ligation appears to be well tolerated in this group of predominantly non-atherosclerotic aneurysms.

Adolescent↗
PubMed2000

Gunshot injuries of the popliteal artery.

BACKGROUND: Guidelines for the management of popliteal artery trauma emanate mainly from military experience. This study was undertaken to describe the management of popliteal injuries in a civilian vascular surgical unit with a large trauma workload. METHODS: A retrospective review of records of patients treated between 1983 and 1997 was undertaken. RESULTS: Some 117 popliteal artery gunshot injuries were treated (83 low velocity, 16 high velocity, 18 shotgun). Associated fractures occurred in 44 patients and 40 had popliteal vein injuries. Treatment of the arterial injury included vein graft interposition in 71, primary reanastomosis in 19, prosthetic graft interposition in four, lateral suture in one, vein patch in one and ligation in one patient; 84 fasciotomies were performed. No perioperative deaths occurred. There were 20 primary and 14 secondary amputations. Factors associated with amputation were high-velocity injuries, delay in revascularization in excess of 7 h, arterial transection, associated fracture, and compartment syndrome or muscle infarction. CONCLUSION: Civilian popliteal gunshot injuries are attended by a high amputation rate. Prompt resuscitation and revascularization appear to be the only correctable factors that may improve limb salvage rates.

Adolescent↗
PubMed2000

Management of penetrating cervicomediastinal venous trauma.

OBJECTIVES: to evaluate the results of management of penetrating cervicomediastinal venous trauma. DESIGN: retrospective study. Materials forty-nine consecutive patients with cervical and thoracic venous injuries treated at a tertiary hospital between 1991 and 1997. Method patients identified from a computerised database and data extracted from case records. RESULTS: forty-five patients were male and the mean age was 25.3 years. Forty injuries were due to stabs and 9 to gunshots. 22 patients were shocked, 25 actively bleeding and 31 were anaemic. Veins injured were internal jugular in 25, subclavian in 15, brachiocephalic in 6, and superior vena cava in 3. Injured veins were ligated in 25 cases and repaired by lateral suture in 22. No complex repairs were performed. There were 8 perioperative deaths and 5 cases of transient postoperative oedema. Venous ligation was not associated with increased risk of postoperative oedema. CONCLUSIONS: ligation is an acceptable form of treatment of cervicomediastinal venous injuries in the presence of haemodynamic instability, or where complex methods of repair would otherwise be necessary.

Adult↗
PubMed2000

Angiographic embolisation in arterial trauma.

OBJECTIVES: to evaluate the use of endovascular occlusion in the treatment of arterial trauma. METHODS: records of patients with penetrating arterial injuries treated by endovascular occlusive techniques were culled from the computerised database of the vascular service. RESULTS: the study period spanned 7 years. Forty-two patients were studied with injuries to the cervicofacial vessels (24), lower limb (16) and upper limb (1). 13 had an arteriovenous fistula. There were 4 failures. In 2 cannulation was not achieved and in 2 with A-VF distal vessel occlusion was impossible. Two patients developed complications. In the remainder, treatment was effective and durable. CONCLUSION: this treatment modality is effective and safe in the treatment of penetrating trauma in selected patients.

Angiography↗
PubMed2000

Clinical profile of HIV-related aneurysms.

OBJECTIVES: to describe the clinical features, management, outcome and laboratory features of human immunodeficiency virus (HIV)-related aneurysms. MATERIALS: twenty-eight HIV positive patients with arterial aneurysms treated at a single university teaching hospital in a 6-year period. METHODS: case review of clinical records and laboratory findings. Specimens from patients surgically treated submitted for microbiological and histological examination. RESULTS: ninety-two aneurysms were seen (range 1-10 per patient) in a young patient population (median age 30 years). Nineteen patients had evidence of advanced HIV infection. Aneurysms were atypically located and most frequently involved the carotid (24), superficial femoral (21) and popliteal (nine) arteries. Twenty-five of the 31 symptomatic aneurysms were treated surgically. Surgical intervention comprised arterial reconstruction for 19 and aneurysm resection and ligation for the remainder. Histological examination revealed distinctive arteritic features. There were two treatment-related deaths, with short-term post-operative outcome being otherwise favourable. CONCLUSIONS: HIV related aneurysms are characterised by their predilection for young patients, multiplicity, atypical location and their distinct histological features. Their increasing frequency reflects the unchecked advance of the HIV epidemic.

Adolescent↗