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Biomedical subjects

K Rajendran

Publications and source records attributed to K Rajendran.

At least 37 records · Page 2Linked to original sources
PubMed2000

Cluster-analysis & patterns of dissemination of multidrug resistance among clinical strains of Vibrio cholerae in Calcutta, India.

BACKGROUND & OBJECTIVES: Antimicrobial resistance among Vibrio cholerae has been monitored for several years in Calcutta. To investigate the changing trends in multidrug resistance (MDR) among different serogroups of V. cholerae and to perform software assisted cluster analysis the current study was undertaken. METHODS: Strains isolated from patients with cholera and "cholera-like" diarrhoea admitted in the Infectious Diseases Hospital, Calcutta were analysed. Eight hundred and forty V. cholerae strains isolated from 1992 through 1997 were tested for susceptibility to 11 antibiotics. Cluster analysis was done using SPSS software. RESULTS: Most of the strains exhibited MDR with fluctuating trends as the resistance profile diverged each year. A total of 119 different resistance profiles exhibited by V. cholerae O1, O139 and non-O1, non-O139 serogroups were analysed by cluster combination method. During 1993 and 1994, 53 per cent of V. cholerae O139 and 82 per cent of V. cholerae O1 serogroups, respectively, exhibited maximal number of new resistance patterns. The frequency of new resistance patterns among V. cholerae non-O1, non-O139 was constantly high (33-47%) during 1995 to 1997. INTERPRETATION & CONCLUSIONS: With a few exceptions, preponderance of the resistance profiles was generally not confined to any serogroup. The cluster analysis depicted dissemination of some of the resistance patterns commonly found among V. cholerae non-O1, non-O139 belonging to different serogroups to the O139 serogroup in the succeeding years. In this study we have shown that the V. cholerae strains are resistant to several antibiotics with constant change in the MDR profiles. It is imperative to define the susceptibility pattern of the strains to determine the effective drug of choice for the treatment of cholera.

Cluster Analysis↗
PubMed1998

Anatomic basis of cleft palate and velopharyngeal surgery: implications from a fresh cadaveric study.

The purpose of this investigation was to apply the findings of an anatomic study of the levator veli palatini, palatopharyngeus, and superior constrictor muscles in 18 fresh cadaveric specimens of normal adults to analyze current controversies in velopharyngeal function and cleft palate surgery. The levator veli palatini was observed to form a muscular sling, suspending the velum from the cranial base. Its fibers occupied the middle 50 percent of the velum, lying in transverse orientation and without significant overlap across the midline. It is well placed to function as the prime mover in the velar component of velopharyngeal closure. The velar component of the palatopharyngeus consisted of two heads clasping the levator and inserting into the latter just short of the midline. Its pharyngeal component inserted into the superior constrictor in the lateral and posterior pharyngeal walls. Together, these two muscles formed a sphincter around the velopharyngeal port, suggesting that both muscles are involved in the pharyngeal component of velopharyngeal closure. Based on the premise that the goal of palatoplasty is to restore normal anatomy, the intravelar veloplasty has a sound basis, and theoretically improves both velar and pharyngeal wall function because it corrects the dysmorphology of both the levator and palatopharyngeus. Although the Furlow palatoplasty also reorients these velar muscles correctly in the transverse position, the resulting overlap of the levator and palatopharyngeus across the midline is morphologically abnormal. In addition, the use of large Z-plasty flaps in wide clefts may cause excessive lateral tension, increasing the risk of fistula formation and causing an impairment of velar stretch capacity. The raising of a vertical pharyngeal flap divides the fibers of the superior constrictor and has the potential to impair pharyngeal wall function. The sphincter pharyngoplasty interferes less with pharyngeal wall anatomy. The potential for an obstructive outcome seems to be related to the use of wide, long flaps and a tight, overlapping type of flap inset. In addition, the level of flap inset is important: an inset at the level of the uvula has the greatest risk of causing obstruction, whereas a higher inset at the level of attempted velopharyngeal closure seems to provide the best opportunity for achieving velopharyngeal competence while avoiding hyponasality and obstruction.

Adult↗
PubMed1998

Clinical implications of the velopharyngeal blood supply: a fresh cadaveric study.

The aim of this investigation was to examine the blood supply of the normal velopharyngeal musculature and its clinical implications. Detailed dissections were performed on each side of five fresh human adult cadaveric head and neck specimens (n = 10) following carotid artery injection with liquid neoprene latex stained with green pigment. The vascular network of the soft palate was situated within its glandular layer. The velopharyngeal muscles were supplied by the following four branches of the external carotid artery: (1) ascending palatine branch of the facial artery, which supplied the palatoglossus, palatopharyngeus, musculus uvulae, and the intravelar part of the levator veli palatini; (2) ascending pharyngeal artery, which supplied the superior constrictor; (3) the previously undescribed recurrent pharyngeal artery, which supplied the extravelar part of the levator veli palatini; and (4) maxillary artery, which supplied the tensor veli palatini. All muscles except the musculus uvulae had at least a dual blood supply. Analysis of this vascular anatomy suggests that (1) the overall generous blood supply of the velum allows it to tolerate the dissection performed during intravelar veloplasty and the Furlow double opposing Z-plasty; (2) dissection around the hamulus, along the medial pterygoid plate, and in the space of Ernst should be performed carefully to avoid damage to the ascending palatine artery, ascending pharyngeal, and recurrent pharyngeal arteries; (3) vertical pharyngeal flaps are random pattern in nature; and (4) the posterior tonsilar pillar flaps of the sphincter pharyngoplasty are adequately supplied by the hamular branch of the ascending palatine artery.

Adult↗
PubMed1997

A fresh cadaveric study of the paratubal muscles: implications for eustachian tube function in cleft palate.

The aims of this anatomic investigation were to examine the levator veli palatini, tensor veli palatini, and salpingopharyngeus muscles in relation to normal eustachian tube function and to analyze the clinical implications of these data for tubal physiology in cleft palate individuals. Detailed dissections under 3.2x loupe magnification were conducted on the paratubal muscles of 15 fresh human adult cadaveric head specimens, paying particular attention to their cranial base anatomy. Each half of the cadaveric heads was examined separately, giving a sample size of 30. The cranial base origin of the levator veli palatini was the junction of the cartilaginous and bony parts of the eustachian tube. Contrary to statements in the existing literature, it had no origin from the quadrate area of the petrous temporal bone. In its path toward the velum, it was related inferiorly and lay almost parallel to the tube. The tensor veli palatini originated from the scaphoid fossa of the sphenoid bone and the tube. In contrast to previous descriptions, it was found to consist of a single sheet of muscle with no bilaminar structure. Its axis was oblique to that of the tube. The salpingopharyngeus was a slender muscle attached to the posteroinferior aspect of the pharyngeal end of the tube. It inserted into the palatopharyngeus inferiorly. These morphologic characteristics and anatomic relationships suggest that (1) the levator veli palatini opens the eustachian tube by isotonic contraction that results in displacement of the medial tubal cartilage and the tubal membrane, (2) the tensor veli palatini opens the tube directly by traction on the lateral tubal membrane and indirectly by rotation of the medial tubal cartilage by means of traction on the lateral tubal cartilage, (3) because of its consistently small size, the salpingopharyngeus is probably functionally the least important of the paratubal muscles, (4) the levator veli palatini is unable to cause tubal dilatation in cleft palate because it can only contract isometrically, and (5) tensor veli palatini function is probably unaffected by clefting. However, its mechanism of action may be disrupted iatrogenically by complete hamular fracture or division of its tendon.

Aged↗
PubMed1997

Structure of the musculus uvulae: functional and surgical implications of an anatomic study.

OBJECTIVE: The role of the musculus uvulae in velopharyngeal function, its morphologic status in cleft palate, and its fate in palatoplasty procedures are subjects of controversy. The aims of this investigation were to re-examine this velar muscle to clarify its anatomic characteristics, to analyze its role in speech physiology, and to study the surgical implications of this information for cleft palate repair. METHODS: Its attachments, morphology, and relations were examined in 18 fresh human adult cadavers by detailed dissection under 3.2x magnification and light microscopy. RESULTS: The musculus uvulae was observed to be a paired midline muscle extending between the tensor aponeurosis anteriorly and the base of the uvula posteriorly along the nasal aspect of the velum. It had no attachments to the hard palate. CONCLUSIONS: These findings suggest that its action is to increase midline bulk on the nasal aspect of the velum, thus contributing to the levator eminence. It may also have an extensor effect on the nasal aspect of the velum, displacing it toward the posterior pharyngeal wall. Both of these actions would serve to maximize midline velopharyngeal contact. One clinical application of this anatomic information is that the muscle should be preserved in the dissection performed during intravelar veloplasty. Furthermore, it should be recognized that the musculus uvulae is invariably divided and reoriented incorrectly in the Furlow double opposing Z-plasty.

Adult↗
PubMed1996

Occurrence of diarrhoeal diseases in relation to infant feeding practices in a rural community in West Bengal, India.

In a rural community-based prospective study, diarrhoea in relation to the feeding patterns of a cohort of infants was studied. A total of 148 infants between the ages of 0 and 2 months were enrolled and followed until the completion of 1 year of age. Survival analysis showed that by the fourth month of age exclusive breastfeeding dropped by 75%. The proportion of complementary breastfeeding increased from 18.6 to 52.9% during the same period and to 83.7% by the eighth month. This study clearly highlights the tendency for early switch over from exclusive breastfeeding to complementary breastfeeding. Early weaning was associated with an incidence rate ratio (IRR) of 3.02 (95% CI 1.043-8.802). The IRR of 3.02 and its confidence limits (1.043-8.02) suggest a significant protective effect of exclusive breastfeeding against diarrhoea in infants. The results of this study indicate that promotion of exclusive breastfeeding has a potential role to reduce the incidence of diarrhoea amongst infants. The findings of this study will be useful for Diarrhoeal Disease Control Programme in reducing diarrhoeal morbidity.

Breast Feeding↗
PubMed1996

Temporal shifts in traits of Vibrio cholerae strains isolated from hospitalized patients in Calcutta: a 3-year (1993 to 1995) analysis.

This study presents results of a surveillance on cholera conducted with hospitalized patients admitted to the Infectious Diseases Hospital, Calcutta, India, from January 1993 to December 1995. The O139 serogroup of Vibrio cholerae dominated in 1993 but was replaced by O1 as the dominant serogroup in 1994 and 1995. The isolation rate of V. cholerae non-O1 non-O139 did not exceed 4.9% throughout the study period, while the isolation rate of the O139 serogroup in 1994 and 1995 was below 9%. No temporal clustering of any non-O1 non-O139 serogroup was observed. With the exception of 1 strain, none of the 64 strains belonging to the non-O1 non-O139 serogroup hybridized with ctx, zot, and ace gene probes, while 97.3 and 97.7% of the O139 and O1 strains, respectively, hybridized with all the three probes. Multiplex PCR studies revealed that all the O1 strains belonged to the EIT or biotype. There was a progressive increase in the cytotoxic response on CHO and HeLa cells evoked by culture supernatants of strains of V. cholerae non-O1 non-O139 isolated during 1994 and 1995 compared with the response evoked by those isolated in 1993. Dramatic shifts in patterns of resistance to antibiotics between strains of V. cholerae belonging to different serogroups and within strains of a serogroup isolated during different time periods were observed. There was a discernible increase in the incidence of multidrug-resistant strains of V. cholerae O1 isolated in 1994 and 1995 compared with that in 1993. On the basis of the results of this study, we predict the possibility of newer variants of V. cholerae emerging in the future.

Drug Resistance, Multiple↗
PubMed1992

The rotary influence of articular contours during passive glenohumeral abduction.

Automatic external rotation at the glenohumeral joint is an essential component of active as well as passive elevation of the arm through abduction. Recent studies have demonstrated this automatic rotation to be present during passive abduction using cadaveric glenohumeral joints even in the absence of extra-articular influences like the coraco-acromial arch and glenohumeral muscles. In the present study, simulated abduction in disarticulated cadaveric joints was shown to be associated with automatic external rotation suggesting a role in this mechanism for the articular contours.

Aged↗
PubMed1991

Glenohumeral abduction and the long head of the biceps.

The role of the long head of the biceps in glenohumeral abduction and the accompanying external rotation is an unsettled issue. Automatic external rotation however has been previously demonstrated during passive abduction, with intact long head and the absence of factors traditionally considered to influence the rotation such as the coracoacromial arch and muscles surrounding the joint. The present study on the anatomy of the tendon of the long head in relation to passive abduction shows that not only is the tendon likely to be harmed by forced abduction without external rotation but the course of the tendon itself is such that activity in the long head during abduction is likely to influence external rotation that in turn prevents tendon impingement between greater tuberosity and glenoid labrum and allows glenohumeral abduction to be carried further towards completion.

Biomechanical Phenomena↗
PubMed1990

The integration of knowledge through interactive Computer-Enhanced Learning in medicine.

Rapid advances in Information Technology in recent years have provided powerful computers and software that can be innovatively applied to create powerful pedagogical courseware that go beyond what precursors like the PLATO project could do on the mainframes of yesteryear. This article focusses on the research and development that we have carried out which is applicable to the whole area of education (including medical education). It introduces the elements of hypertext, hypermedia and the pedagogical user interface. It illustrates the principles necessary for the communication of conceptual, functional and structural knowledge. It emphasises the key aspect of mastery of Information Technology necessary for a new dimension in Computer-Enhanced Learning that will be of relevance to the Information Society of the 21st century.

Computer-Assisted Instruction↗
PubMed1990

The effective learning of spatio temporal concepts of human structure.

The recent availability of increasingly powerful and user friendly computers is making a noticeable impact in the field of medical education. Over the past year, the power of the computer is being harnessed here in the field of anatomy to enable medical and dental students to learn the subject more effectively. Machines with excellent graphics, text and animation capabilities have made it possible to allow students to comprehend structural complexity as seen in gross anatomy or, temporal alterations of structure as seen in embryology by the use of computer based, tutorial style or self paced interactive style of learning. Positive student response to sample learning packages has encouraged the undertaking of courseware development for future use at computer workstations.

Anatomy↗
PubMed1990

Hypertext-based enhancement of medical and dental undergraduate learning.

The use of the microcomputer in medical education began about 1977. Since then man computer-assisted learning packages have been developed for preclinical and clinical subjects. The experiences of the authors with the Macintosh microcomputer in the development of courseware and tutorware on some aspects of Anatomy in the Department of Anatomy of the National University of Singapore are shared in the present paper. It describes how textual and instructive material can be prepared along with graphics support using a software called HYPERCARD (Apple Inc.). Elementary levels of animation can also be achieved. In this way it illustrates how a study of Anatomy, for example, can be made using the computer to "dissect" the human body.

Anatomy↗
PubMed1989

Computer-enhanced learning in neuroanatomy.

The recent development of powerful microcomputers and the introduction of object-oriented programming languages has now made available to educationists software that can be easily used to design and develop computer-based learning material. We have developed courseware and tutorware in the field of neuroanatomy which are pedagogically structured and yet provide multiple paths of learning for the individual student. Neuroanatomy is a difficult subject to learn because of the structural intricacy and functional correlations that it entails. The courseware enables students to approach the subject at different levels of difficulty and progress at their own pace towards a comprehensive understanding of structure and function aided by text integrated with graphics, sound and animation. A significant advantage to authors of similar courseware is the option to update the contents easily when necessary in the future.

Computer-Assisted Instruction↗
PubMed1989

Automatic external rotation during passive glenohumeral abduction.

A study of human cadaveric glenohumeral joints was undertaken to investigate the mechanism of external rotation during abduction. Previously explored extra-articular influences such as the coracoacromial arch and the rotator cuff muscles were removed from the specimens. A specially designed device was used to measure abduction in the scapular plane as well as any rotation of the humerus. The findings show that external rotation is a consistent feature of passive abduction in the plane of the scapula and could take place in the absence of extra-articular influences. The mechanism appears to lie either in the nature of the capsule or of the articular contours. A role for the intra-articular part of the long head of the biceps cannot be excluded.

Aged↗
PubMed1989

The insertion of the iliopsoas as a design favouring lateral rather than medial rotation at the hip joint.

A study of cadaveric material undertaken to investigate a possible anatomical basis for the nature of rotary influence of the iliopsoas at the hip joint shows that the winding course around the femoral neck with extension of tendon insertion towards the greater trochanter, and the spiralling course of the tendon both appear to be a design for causing external rotation during muscular contraction by a process of unwinding around the neck and untwisting of the spiral tendon under tension.

Aged↗
PubMed1985

Mechanism of locking at the knee joint.

The articular contours of the femoral and tibial condyles show certain basic features that in themselves appear sufficient to effect locking at the knee joint during the terminal stages of extension. The essential feature on the femoral condyles is a convex surface adapted for rolling. On the tibia, the contours that chiefly influence rotation are the concave up slope on the anterior portion of the medial condyle that brings the rolling medial femoral condyle to a skidding halt, and the flattening or convex down slope on the anterior part of the lateral tibial condyle that allows the rolling of the lateral femoral condyle to continue further forwards, thus bringing about medial rotation of the shaft. Load on the joint must assist in the locking movement by enhancing the influence of the bony contours.

Aged↗