Carbon dioxide sensitivity during hypoglycaemia-induced, elevated metabolism in the anaesthetized rat

We have utilized an anaesthetized rat model of insulin-induced hypoglycaemia to test the hypothesis that peripheral chemoreceptor gain is augmented during hypermetabolism. Insulin infusion at 0.4 U kg (-1)min(-1) decreased blood glucose concentration significantly to 3.37 +/- 0.12 mmol l(-1). Whole-body metabolism and basal ventilation were elevated without increase in P(a,CO(2)) (altered non-significantly from the control level, to 37.3 +/- 2.6 mmHg). Chemoreceptor gain, measured either as spontaneous ventilatory airflow sensitivity to P(a,CO(2)) during rebreathing, or by phrenic minute activity responses to altered P(a,CO(2)) induced by varying the level of artificial ventilation, was doubled during the period of hypermetabolism. This stimulatory effect was primarily upon the mean inspiratory flow rate, or phrenic ramp component of breathing and was reduced by 75% following bilateral carotid sinus nerve section. In vitro recordings of single carotid body chemoafferents showed that reducing superfusate glucose concentration from 10 mM to 2 mM reduced CO(2) chemosensitivity significantly from 0.007 +/- 0.002 Hz mmHg(-1) to 0.001 +/- 0.002 Hz mmHg(-1). Taken together, these data suggest that the hyperpnoea observed during hypermetabolism might be mediated by an increase in the CO(2) sensitivity of the carotid body, and this effect is not due to the insulin-induced fall in blood glucose concentration.

Effect of temporal synergism of neural oscillations on photorefractoriness in Japanese Quail (Coturnix Coturnix Japonica)

Circadian rhythms in many metabolic functions including neural (transmitters) and hormonal secretion appear to change with physiological condition. It is also reported that seasonal changes in photoperiodism/reproduction and other metabolic conditions may result from a temporal interaction of circadian neural oscillations that change seasonally. To test this hypothesis, the present study was designed to study the effect of temporal synergism of two neural oscillations (serotonin and dopamine) on relative photorefractoriness of Japanese quail. Serotonin and dopamine precursor drugs (5-HTP, 5-hydroxytryptophan and L-DOPA, L-dihydroxyphenylalanine) were administered (intraperitonially 5 mg/100 g body weight) at six different time intervals of 0, 4, 8, 12, 16 and 20 hr in sexually mature quail (>12 weeks old). The birds of control group received two daily injections of normal saline. The treatment was given for 13 days in continuous condition of light and then the quail were shifted to intermediate daylength (LD 13.5:10.5 for experiment 1) and short daylength (LD 8:16 for experiment 2). Six weeks following treatment, birds in intermediate daylength showed regressed cloacal gland and testicular activity except in 12-hr group, which exhibited gonadostimulatory condition. But birds of all the groups in short daylength showed complete regression of cloacal gland after 4 weeks of the treatment. In experiment 3, reproductively quiescent relative photorefractory quail maintained under intermediate daylength (LD 13.5:10.5) received 13 daily injections of 5-HTP and L-DOPA at the interval of 12 hr. At 6 weeks post-treatment, it was observed that unlike cloacal gland of control quail, which remained regressed, that of 12-hr quail showed significant development. These findings indicate that 12-hr temporal interaction of 5-HTP and L-DOPA administration maintained reproductive system in stimulated condition and prevented reproductive regression in photorefractory quail, but did not prevent the onset of scotosensitivity. It is concluded that the 12-hr temporal relationship of circadian serotonergic and dopaminergic oscillations not only eliminates photorefractoriness but may also re-establish photosensitivity in relative photorefractory quail. These findings suggest the regulatory role of neural oscillations and their temporal interaction in the regulation of neuroendocrine-gonadal axis with special reference to photosensitivity/refractoriness.

Average annual risk of tuberculous infection in India

Estimates of the prevalence of tuberculous infection among children 1-9 years of age were available for four defined zones of India from a recently concluded tuberculin survey. These were pooled together and the average annual risk of infection in the country was computed as 1.5%. It was higher in urban areas, at 2.2%, than in rural areas, at 1.3%. The results call for further intensification of tuberculosis control activities, especially in urban areas, greater involvement of private practitioners and information, education and communication (IEC) for high-risk groups, to reduce the diagnostic and treatment delay thereby reducing the transmission of infection in all settings.

Tuberculin sensitivity among children vaccinated with BCG under universal immunization programme

A tuberculin survey was conducted among 45988 children with BCG scar and 54227 children without BCG scar between 1-9 years of age and residing in selected rural areas of three defined zones of India. About 45-60% of the BCG-vaccinated children elicited reactions < 5 mm in size and about 70-80% had reactions < 10 mm. Therefore, in the majority of children (showing tuberculin reaction of < 10 mm), BCG-induced tuberculin sensitivity does not interfere with interpretation of tuberculin test. The study also revealed that a proportion of reactions among BCG vaccinated children in 5-9 mm, 10-14 mm and 15-19 mm range may be attributable to BCG vaccination. Therefore, reactions between 10-14 mm and especially 15-19 mm among the vaccinated children must be interpreted carefully. However, 19 mm was observed as the upper limit for BCG induced tuberculin sensitivity and all reactions >- 20 mm in size may be considered to be due to infection with tubercle bacilli, irrespective of the BCG vaccination status.

Polyneuropathy with osteosclerotic myeloma--POEMS syndrome

A 55-years-old male, who presented with insidious onset gradually progressive sensorimotor polyneuropathy, POEMS-syndrome was diagnosed based on polyneuropathy, splenomegaly, hypothyroidism, the presence of IgG-monoclonal serum protein with osteosclerotic lesions and hyperpigmention of skin. Biopsy of the osteosclerotic lesion from the right superior pubic rami was consistent with plasmocytoma. Electrophysiological studies revealed demyelinating sensorimotor neuropathy and biopsy from sural nerve showed demyelinating neuropathy with secondary axonopathy. The patient showed improvement with radiotherapy. This is a rare systemic disease from the clinical spectrum of plasma cell dyscrasias with polyneuropathy. The importance of POEMS syndrome in the differential diagnosis of polyneuropathies has been emphasized.

Can BCG-vaccinated children be included in tuberculin surveys to estimate the annual risk of tuberculous infection in India?

SETTING

Selected villages in three defined zones of India.

OBJECTIVES

To compare the estimated prevalence of tuberculous infection among children with and without bacille Calmette-Guérin (BCG) scar.

STUDY DESIGN

During a nationwide tuberculin survey, 1-9-year-old children were tuberculin tested using 1TU-PPD RT23 with Tween 80.

RESULTS

In the 5-9 year age group, subgroups of tuberculous infected children could be seen as distinct humps among those with or without BCG scar, but not in those aged 1-4 years. In children aged 1-4 years, the estimated prevalence of infection was respectively 3.5%, 3.8% and 3.6% among children without BCG scar, and 4.8%, 4.7% and 4.5% among children with BCG scar in the western, northern and eastern zones. In those aged 5-9 years, the estimated prevalence was respectively 10.4%, 11.0% and 9.1% among children without BCG scar and 11%, 11.9% and 8.7% among children with BCG scar in the three zones. Thus, in children aged 1-4 years, the estimated prevalence among those with BCG scar was considerably higher than in those without BCG scar. This difference was small in those aged 5-9 years.

CONCLUSION

Tuberculin surveys may be conducted irrespective of BCG scar status among children aged 5-9 years, when BCG vaccination is given using Danish 1331 strain during infancy under the Expanded Program of Immunization.

Protective effect of BCG among children vaccinated under universal immunization programme

A case-control study was conducted to estimate the protective effect of BCG vaccination against tuberculosis among children. The children with suspicion of tuberculosis (TB) attending two hospitals in Bangalore city were registered into the study and subjected to detailed clinical examination and investigations. The presence of BCG scar was taken as evidence of vaccination. Modified Stegen-Jones scoring method was adopted for diagnosing TB. The hospital children with score of 7 were considered as TB cases. Children residing in the neighbourhood of cases were similarly investigated and those scoring 4 were labeled as controls. A total of 118 age-sex matched case-control pairs were identified and final analysis was confined to 113 cases and 109 controls after excluding children with doubtful BCG scar. A low protective effect of BCG vaccination at 31% (not significant, statistically) was observed against TB - all forms combined, among children vaccinated as under Universal Immunization Programme. Though the protective efficacy against extra-pulmonary TB was observed to be higher than for pulmonary TB, it was also not significant, statistically. It will be appropriate to conduct further studies on protection rendered by BCG vaccination against tuberculous meningitis and other severe forms of TB. Besides, the quality of vaccination programme including cold chain maintenance also needs to be evaluated.

A new heterobifunctional reagent for immobilization of biomolecules on glass surface

Synthesis of a new heterobifunctional reagent, [N-(2-trifluoroethanesulfonatoethyl)-N-(methyl)-triethoxysilylpropyl-3-amine] (NTMTA) is described for the immobilization of a variety of biomolecules on glass surface. Its triethoxysilyl group reacts with glass surface and trifluoroethanesulfonate ester structure reacts selectively with aminoalkyl/mercaptoalkyl function in biomolecules. The immobilization can be achieved by two ways involving two steps. The first route involves the reaction of NTMTA with glass beads followed by attachment of aminoalkyl- or mercaptoalkylated biomolecules. The second one involves the reaction of biomolecules, viz., oligonucleotides, proteins, etc., with NTMTA via their aminoalkyl or mercaptoalkyl functions to form a biomolecule conjugate, which is then reacted with glass beads (unmodified) to complete immobilization process. This has been demonstrated by successful immobilization of 5'-mercaptoalkyl- or aminoalkylated oligonucleotides and some commonly used enzymes on glass beads using NTMTA reagent.

Comparative Study of Management of Closed Comminuted Femoral Shaft Fractures with Closed Interlocking Intramedullary Nail and Open Reduction and Dynamic Compression Bridge Plating

Fracture shaft of the femur are life-threatening injuries and can cause severe permanent disability. Nowadays die interlocking nailing is regarded as the operative technique of choice for fracture shaft of femur. However, the advantages and disadvantages have rarely been compared with plate osteosynthesis. This is prospective study to compare the two methods of treatments in terms of time to union, hospital slay (including readmission), wound infection, shortening of limb, delayed union, malunion, joint stiffness and implant failure. 54 patients, age (16 to 66) years, were treated by DCP (22), and interlocking nail (24). Eight patients were lost to follow up. The study was conducted in Services Hospital, Department of Orthopaedics and Ittefaq Hospital, Lahore, Pakistan from June 1996 to Dec 1997. Written consent was taken regarding the type of surgery to be performed. Open fractures of Gustilo Grade n or in, femoral shaft fractures associated with other fractures of the same femur, fractures in immature skeleton and segmental fracture were excluded. Winquist and Hansen classification was used to classify fracture comminution. Patients were alternately allocated. In the plating group, primary bone grafting was done in all cases. Time to union in nailing group was 16.43t2.48 weeks and in plating 19.88±3.46 weeks, p-value<0.05. Mean hospital stay in nailing group was 12.8±2.75 day and plating group 21.1±2.73 days, p>0.05. There were 2 deep infections in the plating group and none in nailing group. There was no shortening of limb in die plating group but 2 patients in the nailing group had shortening of 2 cms. Delayed union occurred in 2 patients in nailing group but 5 in plating group. One patient in the nailing group had external rotation of at least 10 degrees and none in plating group. Two patients in the nailing group had knee stiffness and 6 patients in me plating group. One patient in the nailing group had a broken interlocking screw 2 patients in the plating group had bent plates. Closed interlocking intramedullary nailing as a method of treating closed communited femoral shaft fracture is better than plating in terms of rate of postoperative complication including infection.Key Words: Comminuted fractures shaft of femur, static interlocking nailing and bridge plating.

Hepatotoxic alterations induced by subchronic exposure of rats to formulated fenvalerate (20% EC) by nose only inhalation

OBJECTIVE

Fenvalerate (20% EC) is a synthetic pyrethroid, which is commonly used in India by farmers for the protection of many food and vegetable crops against a wide variety of insects. However, its inhalation toxicity data is very limited in the literature due to the fact that the exposure levels associated with these effects were usually not reported. Hence, inhalation exposure was carried out to investigate the hepatotoxic effects.

METHOD

Adult male rats were exposed to fen for 4 h/day, 5 days a week for 90 days by using Flow Past Nose Only Inhalation Chamber. Sham treated control rats were exposed to compressed air in the inhalation chamber for the same period.

RESULTS

The results indicated hepatomegaly, increased activities of serum clinical enzymes (indicative of liver damage/dysfunction) along with pronounced histopathological damage of liver.

CONCLUSION

The hepatotoxic potential of formulated Fen (20% EC) in rats exposed by nose only inhalation is being reported for the first time and warrant adequate safety measures for human beings exposed to this insecticide, particularly by inhalation route.

Pathological and immunohistochemical study of experimental peste des petits ruminants virus infection in goats

Peste des petits ruminants (PPR) is an emerging, economically important viral disease of goats and sheep in the Indian subcontinent. In the present investigation, 15 hill goats were experimentally infected with 2 ml of 10% splenic suspension of a virulent isolate of PPR virus (PPR/Izatnagar/94) that had caused heavy mortality (>75%) in goats during 1994 outbreaks in northern India. More than 86% (13 of 15) animals died between 9 and 13 days post inoculation at the height of temperature or when temperatures were declining. Necropsy findings included congestion of gastrointestinal tract (GIT), nasal sinuses, consolidation of antero-ventral lobes of lungs, engorged spleen, and occasionally oedematous lymph nodes. Histopathological examination of major organs of GIT revealed degeneration and necrosis of labial mucosa, severe mucosal and submucosal congestion, degeneration and necrosis of intestinal epithelium and lymphoid cell depletion from Peyer's patches along with presence of syncytia at times. Lungs showed broncho-interstitial changes and presence of intracytoplasmic and intranuclear eosinophilic inclusions in alveolar macrophages and syncytial cells. These changes in lungs were frequently complicated with serofibrinous pneumonia (57%, eight of 14). Lymphocytolysis and occasional syncytia formation were evident in the lymphoid tissues. Immunohistochemical (IHC) findings included presence of PPR virus antigen in the labial, intestinal, and bronchiolar epithelial cells, pneumocytes, macrophages and syncytial cells in lungs, and lymphoid (intact and necrotic) and reticular cells in lymphoid organs. The findings of the study indicated the highly virulent nature of the PPR virus isolate (PPR/Izatnagar/94), causing 100% mortality and characteristic pathological changes in the target organs such as lungs, intestines and lymphoid tissues. The results of the IHC study suggested that indirect immunoperoxidase could be an alternative method in the absence of more sophisticated methods of laboratory diagnosis of PPR virus infection in goats.

Augmentation of wound healing by ascorbic acid treatment in mice exposed to gamma-radiation

PURPOSE

Because of the crucial practical importance of acute radiation exposure associated with combined injuries, the study was undertaken to investigate the effect of various doses of ascorbic acid on the survival and healing of wounds in mice exposed to whole-body gamma-radiation.

MATERIALS AND METHODS

Animals were given double-distilled water or different doses of ascorbic acid by intraperitoneal injection before exposure to 0 or 10 Gy whole-body gamma-radiation to evaluate the effect of ascorbic acid on radiation-induced mortality. The animals were monitored daily for the symptoms of radiation sickness and mortality. In a separate experiment, animals were administered with either double-distilled water or different doses of ascorbic acid before exposure to 0 or 6 Gy whole-body gamma-radiation to investigate the effect of ascorbic acid on the irradiated wound. A full-thickness skin wound was created on the dorsum of the irradiated mice and the progression of wound contraction was monitored by capturing video images of the wound at various post-irradiation periods.

RESULT

Treatment of mice with various doses of ascorbic acid elevated survival of mice and a highest number of survivors (67 and 33% for 10 and 30 days post-irradiation) was observed for 250 mg kg(-1) (p<0.002 and<0.02 for 10- and 30-day survival, respectively). Ascorbic acid treatment caused a dose-dependent elevation in the wound contraction and highest contraction was observed for 250 mg kg(-1). The wound contraction was significantly greater at 3 (p<0.005), 6 (<0.05) and 9 (<0.05) days post-irradiation with 250 mg kg(-1) ascorbic acid. The complete healing of the wound was effected by day 22.8 post-irradiation in the ascorbic acid-treated irradiation group.

CONCLUSION

Administration of ascorbic acid protected mice against radiation-induced sickness, mortality and improved healing of wounds after exposure to whole-body gamma-radiation. Additional studies will be directed toward analysing the role of successive administration of ascorbic acid to protect non-target tissues during radiotherapy and in initiating and supporting the cascade of tissue repair processes in radiotherapy delayed wounds.

Construction of oligonucleotide arrays on a glass surface using a heterobifunctional reagent, N-(2-trifluoroethanesulfonatoethyl)-N-(methyl)-triethoxysilylpropyl-3-amine (NTMTA)

A rapid method for construction of oligonucleotide arrays on a glass surface, using a novel heterobifunctional reagent, N-(2-trifluoroethanesulfonatoethyl)-N-(methyl)-triethoxysilylpropyl-3-amine (NTMTA), has been described. The heterobifunctional reagent, NTMTA, carries two different thermoreactive groups. The triethoxysilyl group on one end is specific towards silanol functions on the virgin glass surface, while the trifluoroethanesulfonyl (tresyl) group on the other end of the reagent reacts specifically with aminoalkyl- or mercaptoalkyl- functionalized oligonucleotides. Immobilization of oligonucleotides on a glass surface has been realized via two routes. In the first one (A), 5'- aminoalkyl- or mercaptoalkyl-functionalized oligonucleotides were allowed to react with NTMTA to form a oligonucleotide-triethoxysilyl conjugate which, in a subsequent reaction with unmodified (virgin) glass microslide, results in surface-bound oligonucleotides. In the second route (B), the NTMTA reagent reacts first with a glass microslide whereby it generates trifluoroethanesulfonate ester functions on it, which in a subsequent step react with 5'-aminoalkyl or mercaptoalkyl oligonucleotides to generate support-bound oligonucleotides. Subsequently, the oligonucleotide arrays prepared by both routes were analyzed by hybridization experiments with complementary oligonucleotides. The constructed microarrays were successfully used in single and multiple nucleotide mismatch detection by hybridizing these with fluorescein-labeled complementary oligonucleotides. Further more, the proposed method was compared with the existing methods with respect to immobilization efficiency of oligonucleotides.