Post-traumatic diaphragmatic hernia

Post- traumatic diaphragmatic hernia is not an uncommon sequel. But lack of awareness of this condition may delay in diagnosis and result in life-threatening complications. CT scan is regarded as the investigative tool of choice but some prefer Barium studies in delayed cases of diaphragmatic hernia. Chest X- ray and Ultrasonography of the chest and abdomen may also help in arriving at a diagnosis. An awareness of the condition assisted by the radiological investigations will lead to an early diagnosis and treatment which ultimately helps in managing the patients with diaphragmatic hernias better.

Cough plate versus cough swab in patients with cystic fibrosis; a pilot study

BACKGROUND

Accurate identification of lower respiratory tract pathogens is important in the management of cystic fibrosis patients.

AIM

To evaluate the cough plate as an alternative method of obtaining respiratory samples for microbiological culture.

METHODS AND RESULTS

Using sputum culture as the "gold standard", the cough plate method identified significantly more positive cases than either dry or moistened cough swabs. Of 20 patients who had a positive sputum culture, 16 had a positive culture on cough plate compared to seven positive cultures each on moistened swab and on dry swab respectively.

CONCLUSIONS

In this study cough plates were more sensitive than cough swabs in isolating respiratory pathogens in sputum producers. As patients prefer it, the cough plate merits further evaluation, particularly in non-sputum producers.

Mutational analysis of the signal-sensing domain of ResE histidine kinase from Bacillus subtilis

The Bacillus subtilis ResD-ResE two-component regulatory system activates genes involved in nitrate respiration in response to oxygen limitation or nitric oxide (NO). The sensor kinase ResE activates the response regulator ResD through phosphorylation, which then binds to the regulatory region of genes involved in anaerobiosis to activate their transcription. ResE is composed of an N-terminal signal input domain and a C-terminal catalytic domain. The N-terminal domain contains two transmembrane subdomains and a large extracytoplasmic loop. It also has a cytoplasmic PAS subdomain between the HAMP linker and C-terminal kinase domain. In an attempt to identify the signal-sensing subdomain of ResE, a series of deletions and amino acid substitutions were generated in the N-terminal domain. The results indicated that cytoplasmic ResE lacking the transmembrane segments and the extracytoplasmic loop retains the ability to sense oxygen limitation and NO, which leads to transcriptional activation of ResDE-dependent genes. This activity was eliminated by the deletion of the PAS subdomain, demonstrating that the PAS subdomain participates in signal reception. The study also raised the possibility that the extracytoplasmic region may serve as a second signal-sensing subdomain. This suggests that the extracytoplasmic region could contribute to amplification of ResE activity leading to the robust activation of genes required for anaerobic metabolism in B. subtilis.

Ventral hippocampal NMDA blockade and nicotinic effects on memory function

Nicotinic acetylcholine and NMDA glutamate receptors play critical roles in memory function. The brain areas involved in their interaction are still under investigation. One likely area is the hippocampus. Ventral hippocampal administration of nicotinic antagonists impair memory. Hippocampal administration of NMDA antagonists also cause memory impairments. We evaluated the importance of ventral hippocampal NMDA receptors for nicotinic actions on memory by testing the impact of systemic nicotine on memory with and without administration of the NMDA antagonist dizocilpine into the ventral hippocampus. Sprague-Dawley rats (N=11) trained on the 16-arm radial maze were bilaterally implanted with local infusion cannulae in the ventral hippocampus. The effects on memory function of ventral hippocampal infusions of 0, 2, 6 and 18 microg per side of dizocilpine were examined with and without acute systemic nicotine administration (0 or 0.4 mg/kg). The dizocilpine doses tested did not cause memory deficits by themselves but only did so when given in combination with systemic nicotine. Blocking NMDA ventral hippocampal actions revealed an impairing action of nicotine on memory. Nicotine effects on other non-NMDA hippocampal receptor systems or extra-hippocampal systems may have been left unchecked by the diminished nicotinic effect on ventral hippocampal NMDA receptors.

Prenatal chlorpyrifos exposure in rats causes persistent behavioral alterations

Use of chlorpyrifos (CPF) has been curtailed due to its developmental neurotoxicity. In rats, postnatal CPF administration produces lasting changes in cognitive performance, but less information is available about the effects of prenatal exposure. We administered CPF to pregnant rats on gestational days (GD) 17-20, a peak period of neurogenesis, using doses (1 or 5 mg/kg/day) below the threshold for fetal growth impairment. We then evaluated performance in the T-maze, Figure-8 apparatus and 16-arm radial maze, beginning in adolescence and continuing into adulthood. CPF elicited initial locomotor hyperactivity in the T-maze. Females showed slower habituation in the Fig. 8 maze; no effects were seen in males. In the radial-arm maze, females showed impaired choice accuracy for both working and reference memory and again, males were unaffected. Despite the deficits, all animals eventually learned the maze with continued training. At that point, we challenged them with the muscarinic antagonist, scopolamine, to determine the dependence of behavioral performance on cholinergic function. Whereas control females showed impairment with scopolamine, CPF-exposed females did not, implying that the delayed acquisition of the task had been accomplished through alternative mechanisms. The differences were specific to muscarinic circuits, as control and CPF groups responded similarly to the nicotinic antagonist, mecamylamine. Surprisingly, adverse effects of CPF were greater in the group receiving 1 mg/kg as compared to 5 mg/kg. Promotional effects of acetylcholine (ACh) on cell differentiation may thus help to offset CPF-induced developmental damage that occurs through other noncholinergic mechanisms. Our results indicate that late prenatal exposure to CPF induces long-term changes in cognitive performance that are distinctly gender-selective. Additional defects may be revealed by similar strategies that subject the animals to acute challenges, thus, uncovering the adaptive mechanisms that maintain basal performance.

In vitro regeneration of Hypericum patulum Thunb.--a medicinal plant

A protocol was developed for high frequency plant regeneration in H. patulum by shoot-tip culture. H. patulum plants were collected from a wild source growing at high altitude in the eastern Himalayas. Multiple buds were initiated from shoot-tips cultured on Murashige and Skoog's medium supplemented with BAP, kinetin. Addition of thiamin HCI, Ca-pantothenate and biotin enhanced multiple shoot formation. Upon transfer to phytohormone free liquid medium following a brief exposure to auxin, root formation occurred from the micro shoots . Rooted plants were hardened and transferred to soil. Regeneration potentiality was found to be constant throughout the year in long term cultures.

Micropropagation and in vitro flowering of Rauvolfia tetraphylla; a potent source of anti-hypertension drugs

A simple protocol for in vitro mass multiplication of Rauvolfia tetraphylla (Apocynaceae) has been developed. The endophytic microflora was controlled by adopting integrated measures. Multiple shoot development was achieved on MS + Kin (0.1-0.2 mg/l) + BAP (0.4-0.5 mg/l) media. Rooting from in vitro shoots occurred on NAA containing media. In vitro flowering was induced in shoot multiplication media.

Traumatic subarachnoid-pleural fistula

BACKGROUND

Traumatic subarachnoid-pleural fistula is a very uncommon but important condition. Only 21 cases have been reported so far in the world literature.

METHODS

We encountered 2 cases of subarachnoid-pleural fistula, both in pediatric patients presenting without any neurologic deficit. Whereas our first patient presented with recurrent, rapidly filling clear pleural effusions with an obscure cause, posing a diagnostic problem for the pediatricians, the second patient had trauma to the pleura and dura mater by the sharp edge of Kirschner wire, with impending risk of injury to spinal cord and infection.

RESULTS

Surgical intervention was undertaken after we had a strong suspicion of subarachnoid-pleural fistula in both cases. A subarachnoid-pleural fistula was found at the level of the eleventh thoracic vertebra in the first patient and at the level of the eighth thoracic vertebra in the second patient. Autogenous tissues (mediastinal pleural flap and hammered intercostal muscle covered with methylcellulose) were used to repair the fistula. The subarachnoid space was decompressed with a lumbar drain in the second patient.

CONCLUSIONS

The diagnosis of subarachnoid-pleural fistula is difficult when it is not associated with any neurologic deficit. We found that a high degree of suspicion and early surgical intervention to repair the fistula are rewarding.

High frequency plant regeneration of Cymbopogon martinii (Roxb.) Wats by somatic embryogenesis and organogenesis

Embryogenic callus cultures were obtained upon repeated sub-culture of non-embryogenic callus from nodal segments of Cymbopogon martinii (Roxb.) Wats. Murashige and Skoog's medium supplemented with 1mg/l 2,4-dichlorophenoxyacetic acid and 0.5 mg/l kinetin and Linsmaier and Skoog's medium supplemented with 2mg/l 2,4-dichlorophenoxyacetic acid and 0.4 mg/l kinetin were used as maintenance media for non-embryogenic and embryogenic cultures, respectively. Plant regeneration occurred through organogenesis in MS basal media containing 2 mg/l kinetin, 1 mg/l 6-benzylaminopurine, 0.2 mg/l biotin, 0.2 mg/l Ca-pantothonate and 0.1 mg/l napthalene acetic acid. Embryogenesis was induced in LS medium supplemented with 1 mg/l kinetin, 0.5 mg/l 6-benzylaminopurine and 0.1 mg/l 3-indole acetic acid. Plant regeneration at high frequency was recorded both through organogenesis and embryogenesis in different passages of long term callus cultures.