Polyethylene in knee arthroplasty: A review

Polyethylene (PE) has been used extensively in knee arthroplasty since the mid 20th century. Progress in material manufacturing and processing has led to newer polyethylenes over last few decades with different material properties. It has been established that PE wear in knee arthroplasty causes particle induced osteolysis which is the main reason for late failure and requires revision surgery. Although there are various causes of wear, the properties of PE have long been a matter of investigation as a contributory factor. The advent of newer highly cross linked PE has been shown to improve wear rates in hip arthroplasty but the benefits have not been shown to be of the same degree in knee arthroplasty. The laboratory and clinical studies so far are limited and slightly conflicting in their conclusions. The risks of using highly cross linked PE in knee arthroplasty include tibial post fracture, disruption of locking mechanism, liner fracture which can lead to increased wear and osteolysis. The current evidence suggests that highly cross linked polyethylenes should be used with caution and only considered in younger active patients. The results of a recently completed randomized trial to compare the conventional with high molecular weight PE in knee arthroplasty are awaited.     

Abdominal compartment syndrome--an old syndrome, a new perspective.

The abdominal compartment syndrome is a life threatening condition resulting from pathologic elevation of the intraabdominal pressure. Prompt diagnosis is required to avoid significant sequelae. Diagnosis of this syndrome is based on clinical findings and intra abdominal pressure monitoring. Treatment consists of decompressive laparotomy, which corrects the pathology. Various surgical techniques are described to manage the open abdomen. Despite considerable attention accorded to this disorder, it is still associated with high morbidity and mortality. This review article deals with the identification of risk factors, pathophysiology, diagnostic criteria and treatment of critically ill patients with the abdominal compartment syndrome.     

HP01METALS IN GALLBLADDER CARCINOGENESIS

Carcinoma gallbladder is the commonest malignancy in the Northern part of India. The heavy metals are known carcinogens while trace metals have protective effect. Aim The aim of the study is to estimate the heavy and trace metal (Lead, Zinc, Copper, Cadmium, Chromium, Manganese and Selenium) concentration in serum, bile, tissue and gallstone in patients with gallbladder diseases. Method This is a pilot study conducted in 45 cases (Group – I: 15 cases of carcinoma gallbladder, Group II: 15 patients of cholecystitis with cholelithiasis and Group – III: 15 patients of healthy control), to detect the relationship between the heavy and trace metal concentration and gall bladder carcinoma. Analysis of metal was done using Perkins‐Elmer model 2380 atomic absorption spectrophotometer. Results The serum concentration of copper and nickel was significantly high in carcinoma gallbladder patients as compared to patients with cholecystitis while zinc and selenium is low in carcinoma gallbladder patients. Bile concentration of zinc, selenium and manganese was significantly low in carcinoma gallbladder patients (p < 0.05) as compared to patients of cholelithiasis while cadmium and nickel was high. Tissue concentration of manganese was significantly low in carcinoma gallbladder patients as compared to patients of cholelithiasis while chromium was high. Gallstone concentration of copper, manganese and lead was significantly low in carcinoma gallbladder patients as compared to patients of cholelithiasis. Conclusion The heavy metals are in higher concentration in carcinoma gallbladder while trace metals are in lower concentration indicating possible role of heavy metal in gallbladder carcinogenesis.     

Concurrent exposure to lead,manganese, and cadmium and their distribution to various brain regions,liver, kidney,and testis of growing rats

Growing rats were exposed to 5 mg/L Pb,ad libitum in drinking water, and administered low or high doses of Mn and Cd intraperitoneal (i.p.) for 30 days. Some groups of animals were also administered combinations of Pb + Mn and Pb + Cd in an identical manner. Analysis of Pb, Mn, and Cd in tissue samples showed the expected dose-dependent accumulation when the metal was administered singly. However, combined treatment produced different types of metal shift in different tissues. Enhanced accumulation of all three metals in the brain, Mn in liver, Pb in kidney and Cd in testis and kidney after combined exposure may make target organs vulnerable to the toxic effects of metals, even when encountered at low concentrations. Further, the decreased levels of blood Pb after combined treatment with Cd or Mn suggests that the significance of blood Pb level as a diagnostic aid for Pb toxicity in coexposed conditions may not be of much value. Changes in the metallic distribution within the tissues after coexposure may be the result of a competition between the administered metals for common binding sites.     

Malate and lactate dehydrogenases of a freshwater catfish: impact of endosulfan

A sublethal concentration of technical grade endosulfan (END) inhibited 35 to 55% of the activities of cytoplasmic malate dehydrogenase (cMDH), mitochondrial malate dehydrogenase (mMDH), and lactate dehydrogenase (LDH) in the liver and the skeletal muscle of a freshwater catfish, Clarias batrachus, after 7 days of exposure. The activity remained in the inhibited state up to 28 days. The withdrawal of END from the medium after 1 week of exposure gradually restored the activities to control levels within 21 days in the skeletal muscle and 28 days in the liver. The administration of actinomycin D or cycloheximide between the 14th and the 21st day of the withdrawal of END almost completely inhibited the withdrawal-dependent recovery in the activities of all the three enzymes. This indicates de novo synthesis of the enzymes during the recovery period. A conjoint treatment of END and triiodothyronine (T3) raised the activities of cMDH, mMDH, and LDH in the liver and the skeletal muscle up to the control levels. This shows that the inhibitory effect of END may be relieved in presence of T3. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed few changes in the pattern of cytoplasmic proteins of the liver and the skeletal muscle in response to exposure to END.     

Occular loiasis in a Zambian woman

Asymptomatic infection with Loa loa, an eye worm, is reported in a 32-year old Zambian woman. The patient revealed up to 28% eosinophilia but microfileraemia was not noticed. One gravid female parasite 56 X 0.56 mm, extracted from lower lid of left eye of the patient, is described. Treatment with diethylcarbamazine (DEC) extended over three weeks was successful against another parasite in tissues.     

Postoperative Intravenous Drip Infusion is not Required after Minilaparotomy Cholecystectomy

Objective: To determine if drip infusion should be discontinued after full recovery of the patient from anaesthesia after minilaparotomy cholecystectomy in uncomplicated cases.Design: A randomised controlled clinical trial on 60 patients, from the waiting list, of cholelithiasis/cholecystitis operated by minilaparotomy cholecystectomy between November 1995 to March 1996. 30 patients did not receive postoperative IV drip infusion and in 30 patients 12–24 hours of standard drip transfusion was continued according to the current practice.Setting: Single Surgical Unit, SS Hospital, Banaras Hindu University, Varanasi, India.Main outcome measure: Recognition of clinical indication for continuation of. IV drip infusion after full recovery from anaesthesia.Results: In the cohorts of 30 patients each who were or were not given IV drip infusion after full recovery from anaesthesia following minilaparotomy cholecystectomy the observations on pulse rate, blood pressure, time to first voiding of urine and time to start first oral intake of fluids were identical. However postoperative urinary retention occured in 6 (20%) patients in whom the IV drip infusion was given.Conclusion: There is no clinical indication to continue IV drip infusion after full recovery from anaesthesia in patients operated for minilaparotomy cholecystectomy.