Mitochondrial malic enzyme (EC 1.1.1.40; MEM) was examined by starch-gel electrophoresis on post-mortem brain samples from 453 unrelated subjects of either sex comprising 161 Chinese, 150 Indians and 113 Malays and 29 from other racial groups. The estimated gene frequencies of MEM1 were found to be 0.7111, 0.6100 and 0.6769 in Chinese, Indians and Malays, respectively. No significant deviation from the Hardy-Weinberg equilibrium was observed in Chinese and Malays. However, there was a significant deviation with a deficiency of heterozygotes among Indians. MES did not show any polymorphism.
Dr Rajakumar delivered this lecture at the 14th SMA National Medical Convention on 16.4.1983
Republished in: Republished in: Teng CL, Khoo EM, Ng CJ (editors). Family Medicine, Healthcare and Society: Essays by Dr M K Rajakumar, Second Edition. Kuala Lumpur: Academy of Family Physicians of Malaysia, 2019: 83-90
A patient with a solitary intracranial cryptococcoma of the occipital lobe of the brain and a concomitant granuloma of similar aetiology in the breast is reported. Despite resistance of the causative fungus to 5-fluorocytosine in vitro, the patient responded well to radical excisional surgery and therapy with 5-fluorocytosine.
A series of 18 cases of tuberculous encephalopathy (TBE) in children studied between June 1983 and October 1984 at Queen Elizabeth Hospital, Kota Kinabalu is presented. The data suggest that: the incidence is not as rare as previously thought; the occurrence of TBE is related to the absence of BCG vaccination; the presentation is often late; laboratory data, although helpful is not often confirmatory; early treatment is the key to better outcome; the clinical picture should outweigh laboratory diagnosis in the initial assessment and management.
The clinical syndrome of dialysis encephalopathy which has been observed all over the world has also been seen here. The clinical syndrome and clinical course are reported; it has been associated with high levels of aluminium in untreated water used for haemodialysis. Since the introduction of water treatment, this disease has not been observed.
Demonstration of arrested intracerebral blood flow is the ultimate evidence of brain death. Computerized radionuclide cerebral flow study was done on 18 patients diagnosed clinically as brain dead. Correlation was made with clinical neurophysiological and EEG findings. The criteria for diagnosis of arrested intracerebral perfusion using radionuclide flow study were: non-visualization of blood flow activity in the intracranial arteries during the arterial phase, diffused cerebral activity during the capillary phase and non-filling of venous sinuses during the venous phase; visualization of typical 'hot nasal' activity; the time activity curve over the cerebral hemispheres lacks a bolus effect and instead shows a delayed gradual rise of activity. These features are pathognomonic of brain tamponade.
Arrested intracranial circulation was seen in 16 patients (ten had electrocerebral silence; one had extremely abnormal EEG with small voltage activity and five had no EEG done). In the remaining two patients, some cerebral blood flow was demonstrated (one had no definite cerebral activity and the other had diffused EEG activity).
Radionuclide cerebral flow study is a very sensitive, accurate, safe, simple, rapid and non-invasive modality in confirming brain death and is especially useful in patients on "brain-protection" regime, in hypothermia or in certain metabolic states where diagnosis based on clinical and EEG criteria is difficult. EEG need not be a required procedure once brain death is established by the demonstration of arrested intracranial circulation.
Of the seventy cases of cerebral malaria seen at the Duchess of Kent Hospital, Sandakan between January 1984 and June 1986, 57 (81.4%) were due to plasmodia falciparum and 13 (18.6%) were due to mixed p. vivax--p. falciparum infections. Mixed infection cerebral malaria was associated with a more severe anaemia and may carry a poorer prognosis. Indigenous children under five years of age are particularly at risk of death from mixed infections.
An unusual case of proximal migration of a Hakim's valve intracranially into a porencephalic cyst two years after insertion of the ventriculo-peritoneal shunt in a neonate is reported. The underlying cause is discussed. It is recommended that all shunt should be anchored with nonabsorbable suture material properly on to the pericranium.
Of 36 cases of choriocarcinoma treated at the University Hospital Kuala Lumpur during 1980-84 inclusive, 6 patients were found to have cerebral metastases. Intrathecal methotrexate and combination chemotherapy were started in all cases, with monitoring of tumor growth by serial beta-HCG assays and CT scanning of brain and lung. Chemotherapy was reduced because of severe toxicity in 2 patients, one of whom received radiotherapy to the brain. Four patients (66%) have now been in remission for 2.5-6 years. Two did not respond to therapy and died. The factors involved in therapy and response are discussed.
Dexamethasone has recently been shown to block the production of cachectin (implicated in the pathogenesis of cerebral malaria) if administered prior to endotoxin induction of mouse macrophages. Using the hamster cheek pouch-cerebral malaria model, we tested the hypothesis that dexamethasone is effective as a therapeutic agent in severe malaria if given before some yet undefined trigger point in the disease. Infected hamsters were treated with dexamethasone (0.7 mg/kg) daily on days 7-12, 4-12, or 1-12 post-challenge. When treatment was started on day 1, whole body oxygen consumption (used as a measure of erythrocyte transport to sites of diffusion) on day 12 was greater than (P less than 0.05) that of infected control animals, though the degree of anemia was no different in treated and untreated groups. Furthermore, treatment produced a reduction in monocyte accumulation, capillary malfunction, and monocyte/red blood cell aggregate formation observable in the cheek pouch in vivo and a similar reduction in monocyte presence, capillary pathologic change, and multifocal hemorrhage in the brain on postmortem. These data suggest that mediator(s), whose production can be blocked by pretreatment with dexamethasone, are involved in the pathogenesis of disease leading to death of the Plasmodium berghei infected hamster.
Pregnancy after treatment of choriocarcinoma with cerebral metastases is uncommon. We treated a patient successfully with less-toxic chemotherapeutic agents than those advocated by others together with whole brain irradiation. She subsequently had two uneventful pregnancies.
Cognitive impairment has been reported to occur in minor head injury (concussion). The value of the P300 evoked potential as a measure of cerebral concussion was studied in 20 patients with minor head injury and compared with the data from 20 normal subjects. Significant abnormalities of the P300 latency and amplitude were noted in these patients in the post-concussion period. The abnormalities improved completely on repeat testing. The correlation of the P300 to other parameters of head injury is discussed. The P300 constitutes a simple laboratory test that is sensitive measure of cerebral dysfunction in concussive head injuries.
Paraventricular calcification not previously reported in systemic lupus erythematosus was seen in cranial computed tomograms of two patients with this disorder.
Severe neurological dysfunction was observed in sheep 4 weeks after grazing on Signal grass (Brachiaria decumbens). These neurological disorders included the stamping of forelegs, star-gazing, incoordination, head-pressing against the fence and circling movements. Histologically, numerous vacuolations of various sizes were observed in the white matter of the brain giving rise to a spongy appearance.
Cyclic AMP phosphodiesterase (PDE) activity was assayed in the plasma membrane, mitochondrial and microsomal fractions of rat brain. The specific activity of the enzyme was highest in the plasma membrane fraction followed by mitochondrial and then the microsomal fraction. Phosphodiesterase activity of all three fractions was reduced after pretreatment with lecithinase C (PCase) from Clostridium perfringens but less markedly affected by the pretreatment with sphingomyelinase (SMase) from human placenta. The PDE activity of the plasma membrane fraction was more sensitive to PCase treatment compared with the other two particulate fractions, which showed only a slight loss of activity. Temperature seemed to affect PDE activity of the plasma membrane. The enzyme was quite stable at 30 degrees C but its activity dropped by approximately 46% at 37 degrees C after 90 min of incubation. Pretreatment of the plasma membrane at 30 degrees C with PCase at a concentration of more than 5 U caused a marked loss of PDE activity and the decrease in activity reached a plateau at concentrations above 10 U.
1. The activity of cAMP phosphodiesterase (PDE) was studied in a 10,000 g particulate fraction prepared from rat brain. 2. Phospholipase C such as sphingomyelin choline phosphodiesterase (SMase), phosphatidylinositol phosphodiesterase (PIase) and phosphatidylcholine phosphohydrolase (PCase) were used to deplete phospholipid(s) from the particulate fraction and their effects on PDE activity were investigated. 3. Treatment with SMase or PIase did not affect PDE activity whereas treatment with PCase resulted in inhibition. 4. It was also found that the PCase used not only hydrolyzed phosphatidylcholine but also other phospholipids such as phosphatidylethanolamine, phosphatidylserine and sphingomyelin.