Serotonin inhibits neuronal excitability by activating two-pore domain k+ channels in the entorhinal cortex.

The entorhinal cortex (EC) is regarded as the gateway to the hippocampus; the superficial layers (layers I-III) of the EC convey the cortical input projections to the hippocampus, whereas deep layers of the EC relay hippocampal output projections back to the superficial layers of the EC or to other cortical regions. The superficial layers of the EC receive strong serotonergic projections from the raphe nuclei. However, the function of serotonin in the EC is still elusive. In the present study, we examined the molecular and cellular mechanisms underlying serotonin-mediated inhibition of the neuronal excitability in the superficial layers (layers II and III) of the EC. Application of serotonin inhibited the excitability of stellate and pyramidal neurons in the superficial layers of the EC by activating the TWIK-1 type of the two-pore domain K(+) channels. The effects of 5-HT were mediated via 5-HT(1A) receptors and required the function of Galpha(i3) subunit and protein kinase A. Serotonin-mediated inhibition of EC activity resulted in an inhibition of hippocampal function. Our study provides a cellular mechanism that might at least partially explain the roles of serotonin in many physiological functions and neurological diseases.

First molecular evidence of Bartonella quintana in Pediculus humanus capitis (Phthiraptera: Pediculidae), collected from Nepalese children.

Trench fever is a body louse-borne disease caused by Bartonella quintana Brenner. The recent status of louse infestation in Nepalese children is not well known. We collected head and body lice, Pediculus humanus capitis De Geer and Pediculus humanus humanus L., respectively, from 30 children, including 11 cases of double infestation with both head and body lice. Detection of B. quintana in both louse species identified was carried out by polymerase chain reaction (PCR). PCR products with B. quintana DNA sequences were detected in both head and body lice from two children as well as in body lice derived from two other children. These results demonstrate that head lice may also play a role in the transmission of trench fever.

Prevalence of Nocardia species in the soil of Patiala area.

Five hundred soil samples were examined for Nocardia species in Patiala area by using paraffin bait technique. Forty (8 per cent) yielded Nocardia species. All the forty isolates identified as Nocardia asteroides were pathogenic to white mice.

Identification of family Enterobacteriaceae using a three tube method.

Four hundred isolates of Gram Negative bacilli from different samples were tested by three tube method and conventional tests. An overall agreement between the two methods was 89.5%. Non-agreement was in respect of less stable tests like gas production and motility. This does not reflect adversely on the efficacy and suitability of the method. The three tube method is simple, rapid, economical and accurate, saving both time and material.

Prevalence of R-plasmids and serotypes in intestinal Escherichia coli.

A total of 150 strains of E. coli isolated from faecal samples of normal population (Group I), hospital personnel (Group II) and hospitalised patients (Group III) were studied for the transfer of R-plasmids. Auto-transferable R-plasmids were observed in 72.0, 82.0 and 80.0 per cent of groups I, II and III respectively. 77.0 per cent strains were typable. 04 was the most common serotype found in groups I and II, 0134 in group III.

Perianal hypertrophic donovanosis.

PIP: A case of perianal donovanosis in a 15-year old boy, the 3rd to be reported from Punjab State, is presented. On admission the patient presented with beefy red granuloma with superficial ulcers with well-defined borders on the perianal area, perineum and groins, of 3 years duration. The lesions and biopsy contained donovan bodies. The patient was treated with 1 g streptomycin S04 daily for 27 days without effect. He had previously been given penicillin 1.2 million units, and later chloromycetin 1 g daily for 7 days, also without results. He was finally cured with tetracycline 500 mg q.i.d. for 20 days. This case was due to homosexual assault, but the infection can be fecally transmitted. It is extremely rare in North India.^ieng

Biochemical studies on sporulation in blue-green algae. III. Effect of amino acids on glycogen accumulation.

The effect of 21 amino acids was studied on glycogen accumulation during sporulation in the blue-green alga Anabaena sp. All the amino acids enhanced the initial level of glycogen on the 4th day. The maximum amount of glycogen, on the 20th day, was noticed from L-methionine, L-tyrosine, glycine, and L-histidine supplemented cultures. Others like L-serine, L-valine, L-asparagine, DL-alanine, L-glutamic acid, L-phenylalanine, L-aspartic acid, L-arginine, and DL-lysine come next in the order. On the other hand, L-cysteine and L-cystine, although upto the the 16th day they exhibited higher values of glycogen, did not show much variation in glycogen content over nitrogen-free medium. Except in these two amino acids, in all others initiation of sporulation occurred on the 4th day, resulting in free spores on the 8th day. But in case of L-serine, L-asparagine, L-isoleucine, and L-phenylalanine free spores were noticed only on the 12th day while in DL-lysine they were seen on the 16th day. L-cysteine and L-cystine supplemented media showed free spores on the 20th day as in nitrogen-free control.

Biochemical studies on sporulation in blue-green algae. II. Factors affecting glycogen accumulation.

Inorganic nitrogens sources like nitrate, nitrite enhanced sporulation and glycogen accumulation in Anabaena sp. but ammonium chloride neither influenced sporulation nor glycogen accumulation. Acetate and citrate also stimulated early sporulation and glycogen level was higher over nitrogen free control. Nitrogen and carbon sources in combination proved to be useful in inducing early sporulation and increased content of glycogen. Phosphate and calcium also affected glycogen accumulation significantly, although, the sporulation was found to be of the same order as in nitrogen free medium. Sulphate initiated early sporulation, the mechanism of which is not known.

Biochemical studies on sporulation in blue-green algae. I. Glycogen accumulation.

Glycogen accumulation in vegetative cells of Anabaena sp. is demonstrated to be a light-dependent process. No glycogen accumulation is found in dark or in cultures supplemented with 10(-5) M DCMU in light. Large quantities of glycogen accumulate in cells undergoing sporulation and the amount increased with the onset of maturation of spores.

Hemangioendothelioma of the mandible: report of case.

A case of hemangioendothelioma of the mandible, the third of its kind to involve the jawbone is reported. The radiological appearance of new bone formation is a unique feature in this case. The vascular malignant tumor has a poor prognosis.

Melanotic neuroectodermal tumour of infancy: report of a case.

A case of melanotic neuroectodermal tumour occurring in a seven-month-old male infant is reported. The aetiopathogenesis, clinical features, treatment and prognosis of the condition are discussed. Tumours of the jaw in infancy are extremely rare, and pigmented tumours still rarer. One such case of pigmented tumour of the maxilla is the subject of this report.