Biomedical subjects
Publications and source records attributed to S Ramachandran.
A rapid, mild, and convenient transesterification of triglycerides was obtained using 0.2 N-methanolic (m-trifluoro-methylphenyl) trimethylammonium hydroxide. The method yielded results comparable to those obtained using methanolic sodium methoxide.
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The clinico-pathological features of cardiac and pulmonary involvement were studied in seven cases of fatal leptospirosis. Petechial haemorrhages occurred in the heart and pericardium in all cases with blood-stained pericardial effusions in five. Interstitial myocarditis was noted in five patients and probably caused the changing electrocardiographic abnormalities and clinical cardiovascular effects during the illness. Sub-pleural and intrapulmonary haemorrhages occurred in all seven cases with pleural effusions in four. Pulmonary oedema was a striking feature during the early stages of the illness, while in patients surviving the first week of the disease infiltrative and proliferative lesions were common. The latter type of pulmonary changes occurred at a stage when acute renal failure was improving and were not related to the presence and severity of jaundice. The clinico-pathological profile of pulmonary involvement in leptospirosis appears to fall into an adult respiratory distress syndrome and, when present, carries a serious prognosis and would then be a prime factor in mortality. As clinical manifestations of pulmonary involvement appear late during the clinical illness and may be of abrupt onset, auscultatory and radiological surveillance becomes mandatory in severe leptospiral infections.
A case of amoebic liver abscess is reported in which it is clearly indicated that severe obstructive jaundice can be a predominant clinical feature of the condition. Other clinical manifestations of interest are discussed.
A series of 137 patients with amoebic liver abscess has been studied. Recognition of clearly defined but diverse clinical syndromes was found to be necessary not only in diagnosis but also in planned surgical management. The majority of patients had the classic syndrome of fever, right abdominal or chest pain, hepatomegaly, hepatic tenderness and radiological abnormalities. Other syndromes of presentation included the silent abscess, acute amoebic colitis, the acute abdomen, the intraabdominal lump, the external sinus, pyrexia of obscure origin, obstructive jaundice and renal, pleuro-pulmonary and cardiac symptoms. The syndromes due to an abscess in different parts of the right lobe and in the left lobe of the liver are to some extent distinct. In spite of the varied modes of presentation of amoebic liver abscess, the key to diagnosis is an understanding of the chronological sequence of the disease and its progression from one syndrome to another. Diagnostic methods of value and the mortality are discussed.
High pressure reverse phase liquid chromatography has been employed to rapidly separate saturated and unsaturated fatty acids as the corresponding p-bromophenacyl esters. Through the use of a highly efficient C18 reverse phase column packing, it has also been possible to distinguish among geometrical and positional isomers of the unsaturated acids. The use of ultroviolet-sensitive esters has permitted the detection of low (nanogram range) concentrations of fatty acids. The time required for analysis has been further reduced by employing a novel and rapid method for the preparation of the esters.
Amoebic liver pus has an acidic pH. Hence the pleural aspirate from an amoebic empyema due to rupture of an amoebic liver abscess has an acidic pH. In contrast, the pH of pleural aspirates from effusions and empyema of non-amoebic aetiology were noted to have an alkaline pH. The clinical significance of these observations is discussed.
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The hepatic manifestations were studied in 65 patients having uncomplicated primary attacks of vivax and falciparum malaria. Hepatomegaly due to a "non-specific reactive hepatitis" occurred in 57% of cases. Jaundice occurred in 15% of patients and was invariably associated with hepatomegaly. The clinical syndromes of jaundice and hepatomegaly in uncomplicated primary attacks of malaria have to be distinguished from those related to disorders like viral hepatitis, hepatic amoebiasis, typhoid hepatitis, infectious mononucleosis and Q fever. The causes for the jaundice and the pathogenesis for the hepatic lesions have been discussed.
Serum proteins were estimated in two patient groups, namely (i) 20 cases with proven ameobic liver abscess and (ii) 12 cases with hepatic amoebiasis without demonstrable pus, commonly referred to by the misnomer 'ameobic hepatitis'. In amoebic liver abscess a fall in albumin and an increase in alpha 2 and gamma globulin results in a serum protein pattern somewhat different from that in hepatic amoebiasis without demonstrable pus, where an elevation in gamma globulin was infrequent. Post-therapy serum protein estimations revealed that, irrespective of the presence or absence of pus, a rising gamma globulin level in hepatic amoebiasis may be of prognostic significance and post-treatment surveillance would be necessary in patients showing this type of response.
The renal profile was studied in 61 patients having leptospirosis. Leptospira-induced acute renal failure conformed to one of two distinct clinical patterns, either oliguric on non-oliguric renal failure. The prognosis was excellent in the latter variety of renal failure and mortality was confined to patients with oliguric renal failure, where severe glomerular and widespread tubulo-interstitial lesions were invariably present. These patients had unfavourable prognostic features during life, such as prolonged oliguria and anuria, absence of a diruetic phase, persistent elevations in BUN and persistently low urea excretion. The prognostic significance of the age of the patients, hypotension and jaundice in relation to the occurrence and type of acute renal failure have been discussed. Retrospective observations indicate that both a vasculotoxic or haemorrhagic state and oliguric acute renal failure are important causes for mortality in human leptospiral infections.
In roentgenograms of the chest, it was observed that there was an increase in the difference between the right and left domes of the diaphragm in the right lateral views when compared with the difference present in the posteroanterior views. A difference of 3-5 cm in posteroanterior views and 5-0 cm in the right lateral views, could be considered normal values. The greater difference in the levels of the domes of the diaphragm in the right lateral views was confirmed in a study using hepatic models. Factors responsible for this radiological distortion have been outlined and the clinical significance of this phenomenon in respect to elevation of the right dome of the diaphragm has been discussed.
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High pressure reverse-phase liquid chromatography has been used to separate saturated fatty acids, their methyl esters, polyunsaturated fatty acids, and triglycerides. Rapid separation of fatty acids differing in chain length and number of double bonds has been accomplished. Analysis time was less than 10 min in most cases. The high pressure reverse chromatography resulted in better separations of polyenoic acids than can be accomplished by conventional argentation silicic acid column chromatography. The analyses were carried out on a chemically bonded reverse phase packing, VYDAC reverse phase.
The properties of the 500-fold purified high-molecular-weight lipase have been studied. The rate of hydrolysis of the triglycerides decreases with increasing fatty acid chain length. The lipolytic activity also increases with increase in unsaturation in the fatty acyl moiety. Diglycerides are hydrolyzed at more than twice the rate for triglycerides while monoglycerides are not hydrolyzed. Methyl esters are generally hydrolyzed at a higher rate which increases with increasing chain length of the fatty acid but the enzyme does not act on phospholipids. Emulsifying agents such as Tween 20, gum arabic, and albumin increase the rate of hydrolysis. Metal ions such as Hg2+, Zn2+, Cu2+, and Fe2+ strongly inhibit the lipolytic activity of the high-molecular-weight lipase while Ca2+ or Mg2+ by themselves show no stimulating effect. Treatment of the high-molecular-weight lipase with P-chloromercurybenzoate inhibits hydrolytic activity by 70% while iodoacetic acid has no effect.
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Electrocardiographic abnormalities occurred in 46 per cent of cases uith leptospirosis. Although the individual changes noted do not appear to be of importance, they indicate that sub-clinical cardiac involvement does occur in a significant proportion of the patients. The abnormalities observed include disorders in cardiac rhythm and changes in the P-QRS-T complexes, probably resulting from direct myocardial involvement or from a changing milieu interior. While serial tracings are indicated in patients with acute renal failure of the oliguric variety, repeated tracings may detect more definitely changing patterns which indicate the presence of cardiac involvement in patients with other presentations of the disease.