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Biomedical subjects

J Ravindran

Publications and source records attributed to J Ravindran.

16 recordsLinked to original sources
PubMed1999

Evidence for a new malaria vector species, species E, within the Anopheles culicifacies complex (Diptera: Culicidae).

Female Anopheles culicifacies Giles from Ramanathapuram district, Tamil Nadu state, India, were examined for oocysts and sporozoites and their larval progeny for mitotic karyotype. Collections were made from Mandapam and Uchipuli on the mainland, and Thangachimadam and Pamban on Rameshwaram Island. Of the 451 An. culicifacies females that were collected and dissected, 24 were found positive for Plasmodia (21 for sporozoites and 3 for oocysts). Both acrocentric and submetacentric Y-chromosome karyotypes were observed among the progeny of females from all villages. All 11 iso-female lines whose parental females were positive for sporozoites or oocysts had progeny with submetacentric Y-chromosomes. Total absence of sporozoite-positives among mothers of acrocentric males was evidence of assortative mating between these 2 sympatric populations (i.e., 2 species). We propose that the nonvector population with acrocentric Y-chromosome sons retain the original designation of species B and that the vector population with the submetacentric Y-chromosome sons be designated as species E, a new species.

Animals↗
PubMed1998

Late lateralizing and localizing EEG features of scalp-recorded temporal lobe seizures.

The authors studied the lateralizing value for temporal epileptogenesis of focal or hemispheric EEG ictal features that first appear > or = 5 seconds after hemispheric or diffuse EEG changes or after an artifact-obscured onset, by correlation with side of lobectomy abolishing or producing > or = 90% improvement of complex partial seizures (CPS). One hundred forty-eight seizures in 39 patients rendered seizure-free (SF) by lobectomy lacked early localizing features of which 91 (61%) seizures in 37 (95%) patients had late lateralizing or localizing phenomena. Eighty-seven (96%) of 91 late localizing or lateralizing seizures occurred ipsilateral to lobectomy, involving 35 (95%) of 37 patients. Late contralateral and shifting phenomena occurred in a total of 4 seizures of 2 patients. Among 17 non-SF but > or = 90% improved patients, 30 (48%) of 63 seizures lacking early localizing features showed late localizing or lateralizing phenomena. Of these, twenty (67%) involving 12 (71%) patients occurred ipsilateral to lobectomy. Among the remaining 5 (29%) patients, a total of 5 seizures (17%) were contralateral while 5 (17%) exhibited shifting laterality. These data indicate that seizures with late (> or = 5 seconds) localizing or lateralizing features cannot be discounted when assessing laterality of temporal epileptogenesis but cannot be used as the sole electrographic criterion.

Adolescent↗
PubMed1998

The prevalence of Chlamydia trachomatis in patients with pelvic inflammatory disease.

Chlamydia trachomatis is recognized as the most prevalent sexually transmitted organism in many parts of the world. Most complications associated with chlamydial infection in women and their infants can be avoided by appropriate treatment. However, treatment is often not initiated because infections are frequently asymptomatic. The identification of at risk patients and treatment of these patients is a practical clinical approach in the reduction of transmission and prevention of complications. The prevalence of chlamydial infection among patients with pelvic inflammatory disease admitted to Seremban General Hospital was 22.7%. The difference in seropositivity between PID patients (20.5%) and antenatal controls (2.3%) was statistically significant. The corresponding cervical antigen detection rates were 6.8% and 2.3% respectively. Chlamydial infection should be screened for in gynaecological patients and antibiotic policies should take cognizance of the aetiological role played by this organism in pelvic inflammatory disease.

Adult↗
PubMed1998

A survey of hysterectomy patterns in Malaysia.

A prospective cross-sectional study involving 14 government hospitals was undertaken for a period of 6 months in Malaysia to study the patterns of hysterectomy for gynaecological indications. A total of 707 patients were enrolled in the study consisting of 612 abdominal hysterectomies and 95 vaginal hysterectomies. Fibroids (47.6%) and uterovaginal prolapse (13.4%) formed the main indications for surgery. The initial preoperative diagnosis was accurate in 82.8% of cases. A different pathology from that initially suspected was noted in 118 cases. The overall complication rate was 7.9% but vaginal hysterectomies carried a statistically higher complication rate compared to abdominal hysterectomies. Urinary tract infection was significant in vaginal hysterectomies. Blood transfusion was required in 25.0% of abdominal and 6.3% of vaginal hysterectomies. There were no laparoscopic hysterectomies or mortality in this series.

Adult↗
PubMed1996

Practice patterns of some gynaecologists in Malaysia with regards to prophylactic oophorectomy and hormone replacement therapy.

This study aimed to look at the prevailing practice patterns of gynaecologists with regards to prophylactic oophorectomy and usage of hormone replacement therapy. Questionnaires were sent to the first 200 gynaecologists listed in the membership list of the Obstetrical and Gynaecological Society of Malaysia. The response rate was 30%. The results showed that most gynaecologists would perform prophylactic oophorectomy after the age of 49 years. The result was equivocal for the ages between 45 to 49 years. Of those who retained the ovaries at the age of 45 to the menopause, 55% did so because the ovaries were still functional. Almost all gynaecologists would prescribe hormone replacement therapy (HRT) after oophorectomy and the most commonly prescribed form was the oral type. Thirty-five per cent of gynaecologists claimed that more than 80% of their patients were compliant to HRT. The reasons perceived for the poor compliance were mainly poor knowledge and misconception.

Female↗
PubMed1994

High extracellular GABA levels in hippocampus--as a mechanism of neuronal protection in cerebral ischemia in adrenalectomized gerbils.

Adrenalectomy protects the brain from delayed neuronal damage that occurs following transient forebrain ischemia in gerbils. Gamma-amino butyric acid (GABA) and GABA-mimetic drugs also have a neuro-protective effect. In this study we estimated the extracellular glutamate and GABA levels in the hippocampus during transient forebrain ischemia in adrenelectomized gerbils (n = 8) compared to controls (n = 6). Duration of ischemia was 10 min, and glutamate and GABA levels were measured with in vivo microdialysis. Microdialysis was started 2 h after the placement of a probe (to stabilise baseline) and samples were collected at 10-min intervals. The pattern of glutamate release did not show any difference between adrenelectomized animals and controls. Adrenelectomized animals showed marked increase in GABA levels during ischemia and upto 30 min after ischemia (P = 0.0287, 2-way ANOVA for repeated measurements). The enhanced GABA release may be one of the possible mechanisms of neuronal protection against ischemia in adrenelectomized gerbils.

Adrenalectomy↗
PubMed1994

Decreased glutamate release during hypothyroidism may contribute to protection in cerebral ischemia.

Hypothyroidism protects the brain from the effects of transient forebrain ischemia in gerbils. The mechanism for this protection is not fully understood. In this study we looked at the release of glutamate during ischemia in gerbils exposed to surgical hypothyroidism (n = 7), chemical hypothyroidism (n = 8), and surgical hypothyroidism thyroxine-treated (n = 3) and compared them to control euthyroid animals (n = 8). The duration of ischemia was 10 min. Glutamate release was measured with in vivo microdialysis. Microdialysis analysis began 2 h after the placement of the probes (to stabilize the baseline) and collections were obtained in 10-min samples. During ischemia, there was an increase in the release of glutamate that returned to the baseline within 20 min following the insult. In animals made hypothyroid surgically and chemically, the extent of glutamate release was significantly lower than that in the controls. The release of glutamate in the surgically hypothyroid thyroxine-treated animals was similar to that in controls. The attenuated glutamate release could be a mechanism of protection during ischemia in hypothyroid gerbils.

Animals↗
PubMed1994

Massive ovarian cysts--successful management of two cases.

Massive ovarian cysts are not commonly encountered. They frequently present a challenge to the gynaecologist who is faced with them. Two cases of successful removal of massive ovarian cysts are presented. Successful management would involve recognition of complications which occur at various steps in the treatment.

Adult↗
PubMed1994

Sudden maternal deaths probably due to obstetrical pulmonary embolism in Malaysia for 1991.

Obstetric pulmonary embolism forms the most serious vascular problem during pregnancy. The following report is a retrospective study into maternal deaths in Malaysian mothers probably due to obstetrical pulmonary embolism. Obstetric pulmonary embolism can be divided into amniotic fluid embolism and obstetric blood clot embolism. There were 37 maternal deaths attributable to this cause -9.9 per cent of all maternal deaths to blood clot embolism and 6.7 per cent to amniotic fluid embolism. Most cases were diagnosed clinically because a postmortem examination was not done. Eleven cases of embolism were associated with Caesarean delivery. The typical profile of a Malaysian mother dying from obstetrical pulmonary embolism is that of a Malay mother in the "non-risk" parities of one to four and usually aged between 31-35 years. In the management of these patients, there should be an urgency in diagnosis and improvement in diagnostic procedures. Health staff at all levels should be trained to pick up patients who present with features of deep vein thrombosis.

Adult↗
PubMed1990

The prevalence and outcome of ventricular arrhythmias in acute myocardial infarction.

One hundred and seventy-two consecutive cases of acute myocardial infarction (MI) admitted to a coronary care unit were studied with regard to ventricular arrhythmias--pre-mature ventricular contractions (PVC), ventricular tachycardia (VT) and ventricular fibrillation (VF). Sixty-seven (39%) patients had ventricular arrhythmias (PCC-VT-VF), of whom 17 (9.8%) had VT and 11 (6.4%) VF. VT and VF, but not total arrhythmias, were more common in anterior infarctions. Fifty-six out of 67 (83.5%) of these patients arrived at Accident & Emergency (A&E) within the first six hours of onset of chest pain. Ten out of 11 (91%) patients who had VF did so in the first six hours. PVCs were poor predictors of the occurrence of VF (positive predictive value 5.9%). Forty-three patients (84%) who had PVCs did not develop any further arrhythmias. Spontaneous heart rate had no influence on the occurrence of ventricular arrhythmias. Frequent PVCs were more commonly associated with progression to VT and VF. In 30 cases (88%) lignocaine was effective. There was no death due to VT/VF and all responded to drugs and/or cardioversion.

Adult↗